Enhancing ultrafiltration performance for dairy wastewater treatment using a 3D printed turbulence promoter

Dairy factories annually generate an increasing amount of wastewater, which can cause eutrophication due to high concentrations of amino acids and lipids. To address this issue, membrane technology has emerged as a promising solution, but membrane fouling remains a significant challenge, since it can cause decreased flux, decrease membrane rejection performance, and increased energy demand. This study aimed to reduce membrane fouling by integrated a three-dimensional printed (3DP) turbulence promoter into an ultrafiltration dead-end cell and varying stirring speeds. Two mathematical models, Hermia and resistance-in-series, were used to analyze the fouling process. According to both models, the cake layer formation model indicated the most prevalent fouling mechanism. Specific energy demand, permeate flux, membrane rejection, and membrane reversible and irreversible resistances were measured, calculated, and compared. The results suggest that the combination of an integrated 3DP turbulence promoter and high stirring speeds can effectively reduce membrane fouling in a dairy wastewater treatment module.

Investigation of Different Pre-Treatment Techniques and 3D Printed Turbulence Promoter to Mitigate Membrane Fouling in Dairy Wastewater Module

This study investigates the enhancement of dairy wastewater treatment using chemical and physical pre-treatments coupled with membrane separation techniques to reduce membrane fouling. Two mathematical models, namely the Hermia and resistance-in-series module, were utilized to comprehend the mechanisms of ultrafiltration (UF) membrane fouling. The predominant fouling mechanism was identified by fitting experimental data into four models. The study calculated and compared permeate flux, membrane rejection, and membrane reversible and irreversible resistance values. The gas formation was also evaluated as a post-treatment. The results showed that the pre-treatments improved UF efficiency for flux, retention, and resistance values compared to the control. Chemical pre-treatment was identified as the most effective approach to improve filtration efficiency. Physical treatments after microfiltration (MF) and UF showed better fluxes, retention, and resistance results than ultrasonic pre-treatment followed by UF. The efficacy of a three-dimensionally printed (3DP) turbulence promoter was also examined to mitigate membrane fouling. The integration of the 3DP turbulence promoter enhanced hydrodynamic conditions and increased the shear rate on the membrane surface, shortening filtration time and increasing permeate flux values. This study provides valuable insights into optimizing dairy wastewater treatment and membrane separation techniques, which can have significant implications for sustainable water resource management. The present outcomes clearly recommend the application of hybrid pre-, main- and post-treatments coupled with module-integrated turbulence promoters in dairy wastewater ultrafiltration membrane modules to increase membrane separation efficiencies.

A review on the production of 17-4PH parts using press and sinter technology

The press and sinter method remains the standard among powder metallurgy processes for powdered stainless-steel materials. It delivers low cost, low oxidation rate, and adequate corrosion resistance. Furthermore, 17-4PH is a martensitic stainless-steel that is commonly used for high-strength and medium-ductility stainless steel parts. However, a few studies have investigated the press and sinter method for producing 17-4PH parts. This shortage is due to the high hardness (low compressibility) of 17-4PH powder. Thus, the main objective of this study is to evaluate the press and sinter method in terms of the manufacturing process, the influencing factors, and the theoretical basis of press and sinter methods in conjunction with metal injection molding technology for the production of 17-4PH parts. First, the literature and monographs are examined and summarized to cover the previous results, research progress, development trends, and applications of press and sinter method 17-4PH parts. Following the theoretical analysis, the practical investigation was conducted by producing parts with cold pressing from 800 to 1600 MPa, followed by sintering: the sintering temperature was 1200 °C for one hour under a protective vacuum atmosphere. ImageJ analysis was performed to measure the sinter density. The results showed an increase in relative sinter density from 84.43% to 96.43% for 800 and 1600 MPa, respectively, while the earlier results reached 93.47%. Overall, the press and sinter method enables the production of high-hardness 17-4PH parts with a high density, without using additives like lubricants, wax, or alloying elements.

The obscure object of desire: 'nearly, but clearly not, like me': contingency preference in normal children versus children with autism

The author describes the central role of contingency detection in early socioemotional development. It has been proposed (Gergely & Watson, 1999) that infants are innately equipped with a complex perceptual mechanism, the "contingency detection module," which functions to establish the primary representation of the bodily self as well as the later orientation toward reactive social objects. According to the "contingency switch" model, the target value of the module that is initially genetically set to preferentially explore perfectly response-contingent stimulation is "switched" at around 3 months toward a preference for less-than-perfect social contingencies. It is hypothesized that the primary cause of childhood autism is a genetic defect, due to which the normal process of switching contingency preference at around 3 months does not take place. Preliminary results from an experimental study to test this model are reported. The study contrasts the preferential reactions of normal children and children with autism to perfect versus imitative (high-but-imperfect) contingencies. The results provide support for the contingency switch hypothesis of the etiology of childhood autism.

A contingency-based approach to the etiology of 'disorganized' attachment: the 'flickering switch' hypothesis

The authors present a new approach to the etiology of disorganized attachment based on contingency detection theory. According to this view, the relevant common factor in parental maltreatment and unresolved loss that leads to disorganized attachment has to do with the type of "deviant contingency environment" that both of these conditions generate. In such environments, infants experience periods of being in control followed by periods of sudden loss of control over the caregiver's behavior. The authors hypothesize that this adversely affects the developmental unfolding of the infant's innate "contingency detection module" (Gergely & Watson, 1999), which normally involves a maturational shift around 3 months from an initial attention bias for perfectly contingent stimulation to an emerging preference for less-than-perfect social contingencies. The periodically changing controllability of abusive and dissociating "unresolved" attachment figures is hypothesized to block this process and to lead to the defensive fixation of a dysfunctional "flickering contingency switch" mechanism with two dominant and competing target positions (self-oriented vs. other-oriented). This results in the dissociative style of attention and behavioral organization characteristic of disorganized infant attachment. The authors summarize the preliminary results of an empirical study that provides support for this model in 6.5-month-old infants using a modified Still-Face situation (the Mirror Interaction Situation). The study demonstrates differential emotional and behavioral reactions to sudden loss of maternal contingency and a specific interest in exploring the perfectly contingent self-image in the mirror in infants who at 12 months become categorized as "disorganized" in the Strange Situation.

Experimental protocols for investigating relationships among mother-infant interaction, affect regulation, physiological markers of stress responsiveness, and attachment

Gergely and Watson's (1996) social biofeedback theory of parental affect mirroring applies the conditional probability model of contingency perception to parent-child interactions. Infants are first evaluated at birth on neurological and temperament measures. Infants are also evaluated at 6 and 12 months on tasks that study social interactional determinants, infant attachment, and physiological reactions. The Strange Situation is completed at 12-15 months of age. The authors describe how the combination of these experimental and observational procedures allows specific developmental hypotheses to be investigated about the quality of contingent parental affect regulation, sensitivity to internal states, and security of attachment.

Distinguishing logic from association in the solution of an invisible displacement task by children (Homo sapiens) and dogs (Canis familiaris): using negation of disjunction

Prior research on the ability to solve the Piagetian invisible displacement task has focused on prerequisite representational capacity. This study examines the additional prerequisite of deduction. As in other tasks (e.g., conservation and transitivity), it is difficult to distinguish between behavior that reflects logical inference from behavior that reflects associative generalization. Using the role of negation in logic whereby negative feedback about one belief increases the certainty of another (e.g., a disjunctive syllogism), task-naive dogs (Canis familiaris; n=19) and 4- to 6-year-old children (Homo sapiens; n=24) were given a task wherein a desirable object was shown to have disappeared from a container after it had passed behind 3 separate screens. As predicted, children (as per logic of negated disjunction) tended to increase their speed of checking the 3rd screen after failing to find the object behind the first 2 screens, whereas dogs (as per associative extinction) tended to significantly decrease their speed of checking the 3rd screen after failing to find the object behind the first 2 screens.

Is early differentiation of human behavior a precursor to the 1-year-old's understanding of intentional action? Comment on Legerstee, Barna, and DiAdamo (2000)

In a recent issue of Developmental Psychology, M. Legerstee, J. Barna, and C. DiAdamo (2000) reported a study showing that 6-month-olds expect people to talk to persons rather than to inanimate objects and to manipulate inanimates rather than persons. They interpreted this ability as a "precursor" to later understanding of intentionality. The present article takes issue with the authors' 2 different levels of interpretation that contradict each other and raise problems in their own right. It is suggested that M. Legerstee et al.'s finding is most parsimoniously explained by associative learning and may not constitute a precursor to later understanding of intentionality in any well-defined sense of the term. The present article argues for the importance of differentiating between associative and inferential processes and reviews evidence that the understanding of goal-directed action around 9 months of age involves principle-based inferences.

Attachment and borderline personality disorder. A theory and some evidence

An attachment theory approach to severe personality disorder is described. Evidence is presented that suggests that representations of attachment relationships and attachment behaviors of patients with this diagnosis are commonly disorganized in character. It is argued that the capacity to develop mental representations of mental states in self and other (reflective function) develops in the context of attachment relationships and that disorganization of attachment undermines this process. Such disorganization can be associated with trauma but may also be linked to other biological and psychosocial deficits. Many of the clinical characteristics of patients with borderline personality disorder may be seen as consequences of disordered self-organization and a limited rudimentary capacity to think about behavior in mental state terms. The relevance of this model for the practice of psychotherapy with this group of patients is discussed.

Reapproaching Mahler: new perspectives on normal autism, symbiosis, splitting and libidinal object constancy from cognitive developmental theory

Margaret Mahler's seminal work on the psychological birth of the infant has generated more critical discussion than most other psychoanalytic theories of early development. But while the empirically, theoretically, and methodologically based criticisms of Mahler's theory are generally justified, her critics fail at times to consider some of the intriguing and creative insights that her theoretical formulations tried to capture. This paper attempts to reformulate these insights using the new conceptual tools that current cognitive developmental theory provides. Mahler's stage of normal autism is reconsidered in the light of contingency detection theory as an initial phase of primary preoccupation with self-generated perfectly response-contingent stimulation. Her concept of normal symbiosis is recast with the help of attachment theory's views on homeostatic regulation and the social biofeedback model of affect-reflective mirroring interactions with parents. Finally, her ideas about the development of splitting and libidinal object constancy are reconsidered according to recent theories of early representational development and mentalization.

Goal attribution without agency cues: the perception of 'pure reason' in infancy

The proper domain of naive psychological reasoning is human action and human mental states but such reasoning is frequently applied to non-human phenomena as well. The studies reported in this paper test the validity of the currently widespread belief that this tendency is rooted in the fact that naive psychological reasoning is initially restricted to, and triggered by, the perception of self-initiated movement of agents. We report three habituation experiments which examine the necessary conditions under which infants invoke a psychological principle, namely the principle of rational action, to interpret behaviour as goal directed action. Experiment 1 revealed that the principle of rational action already operates at 9 (but not yet at 6) months of age. Experiment 2 demonstrated that perceptual cues indicating agency, such as self-propulsion, are not necessary prerequisites for interpreting behaviour in terms of the principle of rational action. Experiment 3 confirmed that this effect cannot be attributed to generalisation of agentive properties from one object to another. These results suggest that the domain of naive psychology is initially defined only by the applicability of its core principles and its ontology is not restricted to (featurally identified) object kinds such as persons, animates, or agents. We argue that in its initial state naive psychological reasoning is not a cue-based but a principle-based theory.

Teleological reasoning in infancy: the infant's naive theory of rational action. A reply to Premack and Premack

We argue that Premack and Premack's criticism of our demonstration (Gergely et al., 1995) of interpreting goal-directed action in one year-olds in terms of the principle of rationality are ill-founded, and their suggested alternative test for goal-attribution is open to lower level interpretations. We show that the alterative model they propose for our data in terms of 'appropriate' change of means action is but a somewhat imprecise restatement of our account of the infant's naive theory of rational action. Finally, we elaborate and clarify our model of the teleological stance in infancy which we suggest is an as yet nonmentalistic precursor of the young child's later emerging causal theory of mind.

The social biofeedback theory of parental affect-mirroring: the development of emotional self-awareness and self-control in infancy

The authors present a new theory of parental affect-mirroring and its role in the development of emotional self-awareness and control in infancy. It is proposed that infants first become sensitised to their categorical emotion-states through a natural social biofeedback process provided by the parent's 'marked' reflections of the baby's emotion displays during affect-regulative interactions. They argue that this sensitisation process is mediated (similarly to that of adult biofeedback training) by the mechanism of contingency-detection and maximising. Apart from sensitisation, affect-mirroring serves three further developmental functions: (1) it contributes to the infant's state-regulation; (2) it leads to the establishment of secondary representations that become associated with the infant's primary procedural affect-states providing the cognitive means for accessing and attributing emotions to the self; (3) it results in the development of a generalised communicative code of "marked' expressions characterised by the representational functions of referential decoupling, anchoring and suspension of realistic consequences. They consider the clinical implications of our theory, relating it to current psychodynamic approaches to the functions of parental affect-mirroring. Using their model they identify various types of deviant mirroring styles and speculate about their developmental consequences. Finally, they discuss what role their social biofeedback model may play as a mediating mechanism in the therapeutic process.

Taking the intentional stance at 12 months of age

This paper reports a habituation study indicating that 12-month-old infants can take the "intentional stance" in interpreting the goal-directed spatial behavior of a rational agent. First, we examine previous empirical claims suggesting that the ability to attribute intentions to others emerges during the second half of the first year. It is argued that neither the perceptual evidence (concerning the early ability to discriminate agents), nor the behavioral data (indicating the use of communicative gestures for instrumental purposes) are sufficient to support such claims about the early appearance of a theory of mind, as there are alternative explanations for these phenomena in terms of simpler psychological processes. It is then suggested that to show that an infant indeed attributes an intention to interpret the goal-directed behavior of a rational agent, one needs to demonstrate that the baby can generate an expectation about the most rational future means action that the agent will perform in a new situation to achieve its goal. We then describe a visual habituation study that meets this requirement. The results demonstrate that based on the equifinal structure of an agent's spatial behavior, 12-month-old infants can identify the agent's goal and interpret its actions causally in relation to it. Furthermore, our study indicates that infants of this age are able to evaluate the rationality of the agent's goal-directed actions, which is a necessary requirement for applying the intentional stance. In closing, we discuss some of the theoretical and methodological implications of our study.

Sequential up-regulation of thyroid hormone beta receptor, ornithine transcarbamylase, and carbamyl phosphate synthetase mRNAs in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone-induced metamorphosis

During both spontaneous and thyroid hormone (TH)-induced metamorphosis, the Rana catesbeiana tadpole undergoes postembryonic developmental changes in its liver which are necessary for its transition from an ammonotelic larva to a ureotelic adult. Although this transition ultimately results from marked increases in the activities and/or de novo synthesis of the urea cycle enzymes, the precise molecular means by which TH exerts this tissue-specific response are presently unknown. Recent reports, using RNA from whole Xenopus laevis tadpole homogenates and indirect means of measuring TH receptor (TR) mRNAs, suggest a correlation between the up-regulation of TR beta-mRNAs and the general morphological changes occurring during amphibian metamorphosis. To assess whether or not this same relationship exists in a TH-responsive tissue, such as liver, we isolated and characterized a cDNA clone containing the complete nucleotide sequence for a R. catesbeiana urea cycle enzyme, ornithine transcarbamylase (OTC), as well as a genomic clone containing a portion of the hormone-binding domain of a R. catesbeiana TR beta gene. Through use of these homologous sequences and a heterologous cDNA fragment encoding rat carbamyl phosphate synthetase (CPS), we directly determined the relative levels of the TR beta, OTC, and CPS mRNAs in liver from spontaneous and TH-induced tadpoles. Our results establish that TH affects an up-regulation of mRNAs for its own receptor prior to up-regulating CPS and OTC mRNAs. Moreover, results with cultured tadpole liver demonstrate that TH, in the absence of any other hormonal influence, can affect an up-regulation of both the TR beta and OTC mRNAs.

[Submicroscopic structure of the jejunal mucosa of human fetuses]

Authors investigated the submicroscopic structure of the jejunal mucosa of 6--12 week old human foetuses, obtained from arteficial abortions. It was established, that in this age the jejunal mucosa differentiates and develops intensively. In the third month it is build up of morphological units enterocytes. Their structure is morphologically similar to that of the enterocytes of the adult, although in this age they have no function at all.

Zur Bestimmung der effektiven Masse von Ladungsträgern in ZnS

The reduced effective mass m* of the carriers in ZnS was determined b y means of the Franz- Keldysh-effect. The field dependence of the band gap was calculated using the field dependence of transmission and the slope of the absorption curve. The values of TO* for field directions F Ⅱ c and F ⊥ c and for light polarised E Ⅱ c and E ⊥ c are in the order of 0.02 m0- This is unexpected because this value is one order of magnitude smaller than those of other II-VI compounds.