Moulded pulp products manufacturing with thermoforming

Over the past years, eco‐friendly packaging solutions such as moulded pulp have resonated with a growing number of consumers. Among all of them, the thermoformed products make use of the most recent manufacturing approach that produces high‐quality, thin‐walled items. However, it remains an underresearched area, and the development of an efficient and precise manufacturing process is fundamental in order to increase the implementation of sustainable packaging. With the purpose of setting a step towards in the standardization of design and testing practices of eco‐friendly packaging, this work focused on the characterization of the thermoforming process of moulded pulp products and their characteristics. Three different analyses were carried out for this purpose, covering the dewatering efficiency of the process, a quantification of the moulding geometrical accuracy, and an analysis of the internal microstructure of the parts. Experimental results and statistical analysis show that the dewatering efficiency is mainly governed by the mould's temperature while the duration of the contact time is not influential. In the second investigation, the geometrical accuracy of the mouldability of microfeatures was assessed. The process appeared to be dependently related to the pulp type employed. Finally, the internal microstructure was documented using X‐ray computed tomography. The analysis shows an increase in the internal void fraction linked with an increase in the mould's temperature. The role of the water change of phase in the thermoforming process is also discussed by reference to the work conducted on impulse drying.     

UV-TiO2 photocatalysis-assisted chemical mechanical polishing 4H-SiC wafer

The objective of this study is to propose a photocatalysis-assisted chemical mechanical polishing (PCMP) method for atomic smoothing SiC wafer based on the powerful oxidability of UV photo-excited hydroxyl radical on nano-TiO₂ particles. The study identifies five slurries of different photocatalyst, electron capturer, UV light, and pH value by measuring oxidation reduction potential and static oxidation experiment. After PCMP process, a SiC wafer is examined with optical microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy for information on surface finish and quality, material removal and mechanisms. The study demonstrates that photocatalyst, UV light, electron capturer, and acid environment are necessaries for PCMP process. Among the five PCMP slurries, the one with 1?g of TiO₂, 0.3?g of (NaPO₃)₆, 10?ml H₂O₂, 5?g SiO₂ abrasives under UV light irradiation provides the highest material removal rate of 0.95?µm/h and the best surface finish (Ra?=?0.35?nm) and surface quality. It then discusses how UV light irradiation promotes the chemical oxidation of hydroxyl radical with SiC by forming “Si–C–O,” “Si–O,” “C–O,” and “C?O” on SiC surface. The study concludes that the proposed PCMP is effective and clean manufacturing method for SiC wafer without releasing toxic chemicals to environment and human health.     

Geodesic Gaussian Processes for the Parametric Reconstruction of a Free-Form Surface

Reconstructing a free-form surface from 3-dimensional (3D) noisy measurements is a central problem in inspection, statistical quality control, and reverse engineering. We present a new method for the statistical reconstruction of a free-form surface patch based on 3D point cloud data. The surface is represented parametrically, with each of the three Cartesian coordinates (x, y, z) a function of surface coordinates (u, v), a model form compatible with computer-aided-design (CAD) models. This model form also avoids having to choose one Euclidean coordinate (say, z) as a “response” function of the other two coordinate “locations” (say, x and y), as commonly used in previous Euclidean kriging models of manufacturing data. The (u, v) surface coordinates are computed using parameterization algorithms from the manifold learning and computer graphics literature. These are then used as locations in a spatial Gaussian process model that considers correlations between two points on the surface a function of their geodesic distance on the surface, rather than a function of their Euclidean distances over the xy plane. We show how the proposed geodesic Gaussian process (GGP) approach better reconstructs the true surface, filtering the measurement noise, than when using a standard Euclidean kriging model of the “heights”, that is, z(x, y). The methodology is applied to simulated surface data and to a real dataset obtained with a noncontact laser scanner. Supplementary materials are available online.     

Efficient Sampling by Artificial Attributes

Hypotheses about the fraction of items in a lot possessing a “specification attribute” X < L can be tested by generally sampling the variable X or directly sampling the attribute of interest. When the process variance is known, it is often more efficient to test against “compressed limits” for one or more “artificial” attributes X < L_a , X < L_b etc.

This study discusses the efficient choice of one or two compressed limits. General guidelines for this choice are suggested, and then evaluated under many hypothetical test specifications. One compressed limit offered ~40% – 97% savings over direct attribute sampling; two limits allowed about 20% further savings.     

A Comment on Ridge Regression. Biased Estimation for Non-Orthogonal Problems

In a recent issue of Technometrics, Hoer1 and Kennard [l] presented a comprehensive discussion of the problem of biased estimation in multiple regression that fits into the general linear hypothesis model of full rank. An alternative characterization of the form of the biased estimator has been presented in this note, and an “existence theorem” proven indicating that there exists a k such that the biased estimation based on the proposed characterization would still lead to increased accuracy.     

Relationship Between System Failure Rate and Component Failure Rates

A simple sufficient condition is given for a system to have an increasing failure rate when the identical components comprising it have an increasing failure rate. Systems which function if and only if at least k of the n components function (“k out of n” systems) satisfy this condition. For systems of non-identical components, upper and lower bounds on failure rate are obtained in terms of component failure rates. These bounds are increasing functions of time for “k out of n” structures having components with increasing failure rates.     

RETRACTED ARTICLE: The effects of ZrO2 nanoparticles on strength assessments and water permeability of concrete in different curing media

We the Editor and Publisher of Journal of Experimental Nanoscience retract the following three articles: 1. Nazari, Ali, and Shadi Riahi. “The effects of ZnO2 nanoparticles on split tensile strength of self-compacting concrete.” Journal of Experimental Nanoscience 7.5 (2012): 491-512, https://www.tandfonline.com/doi/full/10.1080/17458080.2010.524669

2. Nazari, Ali, and Shadi Riahi. “The effects of SnO2 nanoparticles on physical and mechanical properties of high-strength self-compacting concrete.” Journal of Experimental Nanoscience 7.5 (2012): 559-577, https://www.tandfonline.com/doi/full/10.1080/17458080.2010.543991

3. Nazari, Ali, and Shadi Riahi. “The effects of ZrO2 nanoparticles on strength assessments and water permeability of concrete in different curing media.” Journal of Experimental Nanoscience 8.4 (2013): 413-433, https://www.tandfonline.com/doi/full/10.1080/17458080.2011.586369

Since publication it has come to our attention that these articles duplicate significant parts of other papers published elsewhere and that these were not referenced within these articles (listed above). Following COPE guidelines, Taylor & Francis has tried numerous times to contact the authors as well as their affiliated institutes with a request for clarification, however, we failed to receive a response.

As we have been able to verify that unreferenced content has been duplicated, we have decided to retract these articles. We apologize to the readers that this was not detected during the submission process.

We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.

The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.     

A Forceful “Dendrite-Killer” of Polyoxomolybdate with Reusability Effectively Dominating Dendrite‑Free Lithium Metal Anode

In this work, a series of Mo-containing polyoxometalates (POMs) modified separators to inhibit the growth of lithium dendrites, and thus improving the lifespan and safety of the cells is proposed. When the deposited lithium forms dendrites and touches the separator, the optimized Dawson-type POM of (NH₄)₆[P₂Mo₁₈O₆₂]·11H₂O (P₂Mo₁₈) with the stronger oxidizability, acts like a “killer”, is more inclined to oxidize Li⁰ into Li⁺, thus weakening the lethality of lithium dendrites. The above process is accompanied by the formation of Li_x[P₂Mo₁₈O₆₂] (x = 6–10) in its reduced state. Converting to the stripping process, the reduced state Li_x[P₂Mo₁₈O₆₂] (x = 6–10) can be reoxidized to P₂Mo₁₈, which achieves the reusability of P₂Mo₁₈ functional material. Meanwhile, lithium ions are released into the cell system to participate in the subsequent electrochemical cycles, thus the undesired lithium dendrites are converted into usable lithium ions to prevent the generation of “dead lithium”. As a result, the Li//Li symmetrical cell with P₂Mo₁₈ modified separator delivers exceptional cyclic stability for over 1000 h at 3 mA cm⁻² and 5 mAh cm⁻², and the assembled Li–S full cell maintains superior reversible capacity of 600 mAh g⁻¹ after 200 cycles at 2 C.     

The Impact of a Dynamic Two‐Step Solution Process on Film Formation of Cs0.15(MA0.7FA0.3)0.85PbI3 Perovskite and Solar Cell Performance

This paper provides deep understanding of the formation mechanism of perovskite film fabricated by sequential solution‐based methods. It compares two sequential spin‐coating methods for Cs_0.15(MA_0.7FA_0.3)_0.85PbI₃ perovskite. First is the “static process,” with a stoppage between the two spin‐coating steps (1st PbI₂‐CsI‐dimethyl sulfoxide (DMSO)‐dimethylformamide (DMF) and 2nd methylammonium iodide (MAI)‐formamidinium iodide (FAI)‐isopropyl alcohol). Second is the “dynamic process,” where the 2nd precursor is dispensed while the substrate is still spinning from the 1st step. For the first time, such a dynamic process is used for Cs_0.15(MA_0.7FA_0.3)_0.85PbI₃ perovskite. Characterizations reveal improved film formation with the dynamic process due to the “retainment” of DMSO‐complex necessary for the intermediate phase which i) promotes intercalation between precursors and ii) slows down perovskite crystallization for full conversion. The comparison on as‐deposited perovskite before annealing indicates a more ordered film using this dynamic process. This results in a thicker, more uniform film with higher degree of preferred crystal orientation and higher carrier lifetime after annealing. Therefore, dynamic‐processed devices present better performance repeatability, achieving a higher average efficiency of 17.0% compared to static ones (15.0%). The new insights provided by this work are important for perovskite solar cells processed sequentially as the process has greater flexibility in resolving solvent incompatibility, allowing separate optimizations and allowing different deposition methods.     

RETRACTED ARTICLE: The effects of ZnO2 nanoparticles on split tensile strength of self-compacting concrete

We the Editor and Publisher of Journal of Experimental Nanoscience retract the following three articles: 1. Nazari, Ali, and Shadi Riahi. “The effects of ZnO2 nanoparticles on split tensile strength of self-compacting concrete.” Journal of Experimental Nanoscience 7.5 (2012): 491-512, https://www.tandfonline.com/doi/full/10.1080/17458080.2010.524669

2. Nazari, Ali, and Shadi Riahi. “The effects of SnO2 nanoparticles on physical and mechanical properties of high-strength self-compacting concrete.” Journal of Experimental Nanoscience 7.5 (2012): 559-577, https://www.tandfonline.com/doi/full/10.1080/17458080.2010.543991

3. Nazari, Ali, and Shadi Riahi. “The effects of ZrO2 nanoparticles on strength assessments and water permeability of concrete in different curing media.” Journal of Experimental Nanoscience 8.4 (2013): 413-433, https://www.tandfonline.com/doi/full/10.1080/17458080.2011.586369

Since publication it has come to our attention that these articles duplicate significant parts of other papers published elsewhere and that these were not referenced within these articles (listed above). Following COPE guidelines, Taylor & Francis has tried numerous times to contact the authors as well as their affiliated institutes with a request for clarification, however, we failed to receive a response.

As we have been able to verify that unreferenced content has been duplicated, we have decided to retract these articles. We apologize to the readers that this was not detected during the submission process.

We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.

The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.     

RETRACTED ARTICLE: The effects of SnO2 nanoparticles on physical and mechanical properties of high-strength self-compacting concrete

We the Editor and Publisher of Journal of Experimental Nanoscience retract the following three articles: 1. Nazari, Ali, and Shadi Riahi. “The effects of ZnO2 nanoparticles on split tensile strength of self-compacting concrete.” Journal of Experimental Nanoscience 7.5 (2012): 491-512, https://www.tandfonline.com/doi/full/10.1080/17458080.2010.524669

2. Nazari, Ali, and Shadi Riahi. “The effects of SnO2 nanoparticles on physical and mechanical properties of high-strength self-compacting concrete.” Journal of Experimental Nanoscience 7.5 (2012): 559-577, https://www.tandfonline.com/doi/full/10.1080/17458080.2010.543991

3. Nazari, Ali, and Shadi Riahi. “The effects of ZrO2 nanoparticles on strength assessments and water permeability of concrete in different curing media.” Journal of Experimental Nanoscience 8.4 (2013): 413-433, https://www.tandfonline.com/doi/full/10.1080/17458080.2011.586369

Since publication it has come to our attention that these articles duplicate significant parts of other papers published elsewhere and that these were not referenced within these articles (listed above). Following COPE guidelines, Taylor & Francis has tried numerous times to contact the authors as well as their affiliated institutes with a request for clarification, however, we failed to receive a response.

As we have been able to verify that unreferenced content has been duplicated, we have decided to retract these articles. We apologize to the readers that this was not detected during the submission process.

We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.

The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.     

Load dependence of the apparent Knoop hardness of SiC ceramics in a wide range of loads

Silicon carbide (SiC) ceramics is a material with increasing use, due to its excellent mechanical properties, especially high hardness. In order to integrate this material into design process, we need to know its hardness as precise as possible. The Knoop hardness number (HK) is calculated using the expression: HK = α·F/d², where F is the applied load, d is the long diagonal of the resulting 1₀indentation and a is the Knoop indenter geometrical constant. In this paper, the Knoop hardness of SiC ceramics was measured in the applied load range from 4.9 to 98.07 N. For some materials measured “apparent” hardness value decreases with increasing applied test load (normal indentation size effect – ISE), while for some materials measured “apparent” hardness increases with increasing applied test load (reverse indentation size effect – RISE). Obtained results show the measured hardness exhibits the ISE. In the literature several models are given for the phenomenon explanation. We used the following models: Meyer's law (F = K·dⁿ), proportional specimen resistance – PSR (F = a₁·d + a₂·d²) and modified proportional specimen resistance – MPSR model (F = a₀ + a₁·d + a₂·d²). Results of regression analysis for all applied models show they can all be used for ISE analysis. “True” hardness was determined based on the PSR and MPSR model (HK_T = α·a₂). The obtained results were similar. If the specimen surface is carefully prepared and the range of loads is wide, the a₀ coefficient from MPSR model reaches small values and can be excluded. Therefore, for the calculation of SiC ceramics Knoop hardness, the simpler model (PSR) can be used.     

Dissertation Review

ABSTRACT

The focus of this paper is on innovation, quality, and productivity. Most American enterprises do not understand the innovation process, but confuse it with the invention process. Illustrations of the application of quality management principles in R&;D, concentrating on the innovation process, are given. Discussed are the implications flowing from the principle that “workers work in a system; the job of the manager is to work on the system to improve it with their help.” Also discussed are the definition of the “internal customer,” flow charting, and Quality Function Deployment.     

Organizing distributed data bases for parallel searching

Abstract

This paper is mainly concerned with the problem of distributing a data base (i.e., a set of segments) in a computer network system so as to facilitate parallel searching. In our distributed data base model, we assume that all segments are stored in nodes. Each time a query occurs, all nodes are searched concurrently. For convenience, we define the time required to access a segment from any node as a time unit. For a network with d nodes, the response time of a query is then identical to the maximum (n ₁ , n ₂, …, n_d ), where n_i , is the number of segments that satisfies the query and is stored in node i. Unfortunately, the solution for finding an optimal way to organize a distributed data base for parallel searching is still at large. In other words, given a data base, there is no efficient polynomial time algorithm for finding an optimal arrangement of segments onto nodes. In this article, we shall present a “heuristic algorithm” based upon a multivariant analysis method in statistics to distribute a data base in a network system. Some experimental results will show that our method is indeed feasible and effective.     

The Performance of Some Rough Tests for Bivariate Normality Before and After Coordinate Transformations to Normality

Some rough tests for bivariate normality are employed in an attempt to quantify the intuitive notion that coordinate transformations to normality produce distributions which are “more bivariate normal” than the original variables. These tests are not rigorous procedures but are intuitively satisfying, based on natural statistics, and provide numerical measures of the “distance” of a bivariate distribution from the normal model. It is shown that, for a wide class of non-normal (X, Y) distributions, coordinate transformations to normality decrease this distance as measured by these tests. It is indicated how one may estimate the coordinate transformations and applications to correlation theory are explored.     

Schumpeter, Business Cycles and Co-evolution

In Business Cycles (1939 Schumpeter, J. A. 1939. Business Cycles, New York: McGraw‐Hill.  [Google Scholar]) Schumpeter took up empirical data which had been produced by Kondratieff, and made the “clustering” of innovations into the actual cause of long economic cycles. The book was a failure, largely due to negative reviews which stressed the poor quality of its statistical analysis. In fact, an even more serious fault in it is its reflection of a near‐total blind spot in Schumpeter's perspective about the part played by law in economic life. He thought that “It is entirely immaterial whether or not [changes in the institutional framework] are embodied in, or recognized by, legislation.” The reality is that the concept of co‐evolution of technology and ways of doing business, on the one hand, and legal changes which affect the conditions for investment in them, on the other, explain long cycles much more persuasively than Schumpeter's approach. It suggests that the first Kondratieff cycle was made possible by the availability of “full” property rights, the second by general limited liability law (which Schumpeter thought was “of comparatively small importance”) and the third by new patent legislation which made corporate investment in R&;D attractive. Schumpeter only discussed three cycles, but a co‐evolutionary perspective makes it possible to envisage a fourth cycle as dependent upon the trademark laws which sustain advertising and mass markets, and a fifth one, in which the entertainment and information industries have been similarly underwritten by copyright law. The most plausible reason why Schumpeter undervalued laws was his attraction to the economic interpretation of history. According to this, laws, like ideas, are no more than reflections on a psychic level of social and economic realities, and have little or no power to shape these. For Keynes, in contrast, “it is ideas, not vested interests, that are dangerous for good or ill”. There was consequently no place for co‐evolution in Schumpeter's thought. But what made him publish a book which he described as “a house which is not finished and furnished”, when he did? It could be that the stimulus was evidence of the huge fame which Keynes's General Theory was already winning.     

Beyond recipes: The Baconian natural and experimental histories as an epistemic genre

In 1622, Francis Bacon published his Historia naturalis et experimentalis. Many of the features of Bacon's natural and experimental histories were entirely new. This paper studies this literary form as a new epistemic genre. In particular, it analyzes its origin and evolution in Bacon's work, focusing on how its basic template and features were influenced by his specific epistemic requirements. It shows that Bacon devised these features in the process of developing a Historia mechanica, or a history of the mechanical arts, drawing on the particular case of the technical recipe. Since antiquity, the recipe had been the dominant epistemic genre for recording and communicating technical knowledge. However, this paper suggests that the recipe format did not meet Francis Bacon's epistemic needs. In particular, the format was incompatible with the goal of keeping experimentation and its reporting open-ended and flexible. More generally, the acknowledgment of the provisional, historical character of knowledge was a tenet of what Bacon called an “initiative” method of knowledge transmission, or a method of “probation.” According to this approach, knowledge “ought to be delivered and intimated, if it were possible, in the same method wherein it was invented” and discovered. Only the display of its tentative features would encourage and stimulate others to improve and advance it. The format of the new genre of natural and experimental histories grew out of Bacon's dissatisfaction with the way in which recipes hid the imperfection of the process of knowledge production.     

A simplified fabrication process for biofiber-reinforced polymer composites for automotive interior trim applications

A simplified process was developed for fabricating natural bio-based fiber-reinforced polymer composites for applications such as automotive interior trim substrates. Biofiber (Kraft pulp fiber) and four types of thermoplastic polymers (PP, two PP/PE polymer blends, and PLA) were first wet-formed into fiber/polymer mats and the mats were made into composites using a match-mold thermoforming process. The effects of void content on the composite tensile and flexural properties were investigated. Impact resistance and heat deflection temperature were tested and acoustic absorption coefficients of the composites were evaluated as well. Two types of prototype panels (2-D and 3-D) containing biofiber/polymer composite substrates with a bonded synthetic leather decorative surface were successfully made using this process. Biofiber/PP composites had comparable performance to the commercially available non-wood natural fiber/PP composite counterparts for the properties investigated in this study at the same density level (0.8 g/cm³).     

THE IMPACT FATIGUE PROPERTIES OF PEARLITIC PLAIN CARBON STEELS

A literature search has revealed that the most extensive study of impact fatigue reported is still that of Stanton and Bairstow (1908) who were the first to work on this topic. Their results, which were on pearlitic plain carbon steels, have been reanalyzed in an attempt to deduce from them the effects of chemical composition on impact fatigue in this class of materials. The results show that when the number of impacts to failure, N_f, is greater than about 10³, N_f and the energy absorbed per impact, E_i, are related by the equation: E_i, =E_o+E_kN_f^?p, where E_o appears to be the impact endurance limit. It is suggested that E_k and p be named respectively the “impact fatigue parameter” and “impact fatigue exponent”. E_k is independent of composition except that it is lower by a factor of about four for two materials which probably failed by an intercrystalline rather than transcrystalline fracture; p has a value of 0.6; and E_o increases monotonically with silicon content but does not vary systematically with the carbon, manganese, sulphur or phorphorus contents. The significance of these results is discussed.