Dual feed progressive cavity pump extrusion system for functionally graded direct ink write 3D printing

Material extrusion Additive Manufacturing (AM), is one of the most widely practiced methods of AM. Fused Filament Fabrication (FFF) is what most associate with AM, as it is relatively inexpensive, and highly accessible, involving feeding plastic filament into a hot-end that melts and extrudes from a nozzle as the toolhead moves along the toolpath. Direct Ink Write (DIW) 3D printing falls into this same category of AM, however is primarily practiced in laboratory settings to construct novel parts from flowable feedstock materials. DIW printers are relatively expensive and often depend on custom software to print a part, limiting user-specificity. There have been recent advancements in multi-material and functionally graded DIW, but the systems are highly custom and the methods used to achieve multi-material prints are openly available to the public. The following article outlines the construction and operation method of a DIW system that is capable of printing that can produce compositionally-graded components using a dual feed progressive cavity pump extruder equipped with a dynamic mixer. The extruder and its capabilities to vary material composition while printing are demonstrated using a Prusa i3 MK3S+ desktop fused filament fabrication printer as the gantry system. This provides users ease of operation, and the capability of further tailoring to specific needs.

A Comparison of Non-Destructive Visceral Swab and Tissue Biopsy Sampling Methods for Genotyping-by-Sequencing in the Freshwater Mussel Fusconaia askewi

Limiting harm to organisms caused by genetic sampling is an important consideration for rare species, and a number of non-destructive sampling techniques have been developed to address this issue in freshwater mussels. Two methods, visceral swabbing and tissue biopsies, have proven to be effective for DNA sampling, though it is unclear as to which method is preferable for genotyping-by-sequencing (GBS). Tissue biopsies may cause undue stress and damage to organisms, while visceral swabbing potentially reduces the chance of such harm. Our study compared the efficacy of these two DNA sampling methods for generating GBS data for the unionid freshwater mussel, the Texas pigtoe (Fusconaia askewi). Our results find both methods generate quality sequence data, though some considerations are in order. Tissue biopsies produced significantly higher DNA concentrations and larger numbers of reads when compared with swabs, though there was no significant association between starting DNA concentration and number of reads generated. Swabbing produced greater sequence depth (more reads per sequence), while tissue biopsies revealed greater coverage across the genome (at lower sequence depth). Patterns of genomic variation as characterized in principal component analyses were similar regardless of the sampling method, suggesting that the less invasive swabbing is a viable option for producing quality GBS data in these organisms.

Evaluating the bis-isoxazole core for energetic heterocyclic-based oligomers

Heterocyclic energetic polymers can bridge the gap between inert and detonable energetic materials.

Controlling Material Reactivity Using Architecture

3D-printing methods are used to generate reactive material architectures. Several geometric parameters are observed to influence the resultant flame propagation velocity, indicating that the architecture can be utilized to control reactivity. Two different architectures, channels and hurdles, are generated, and thin films of thermite are deposited onto the surface. The architecture offers an additional route to control, at will, the energy release rate in reactive composite materials.

Understanding the relationship between religiosity and marriage: an investigation of the immediate and longitudinal effects of religiosity on newlywed couples

The association between religiosity and marital outcome has been repeatedly demonstrated, but a complete understanding of this relationship is hindered by limitations of theory and method. The purpose of the current study was to test 3 explanatory models by assessing 2 samples of newlywed couples. Findings indicated that religiosity was associated with attitudes toward divorce, commitment, and help seeking cross-sectionally. Longitudinal effects, however, were most consistent with a moderating model, wherein religiosity had a positive impact on husbands' and wives' marital satisfaction for couples with less neurotic husbands and a negative impact for couples with more neurotic husbands. Overall, the impact of religiosity was weak over the first 4 years of marriage. Theoretical propositions are offered to guide future research in delineating the types of marriages that may be most affected by religiosity.

Are premarital prevention programs reaching couples at risk for marital dysfunction?

In 2 studies, newlyweds reported whether they had participated in premarital counseling and provided data on known risk factors for marital dysfunction. Couples who participated in premarital programs were not at greater risk for marital difficulties, and in some cases participating husbands were at lower risk for marital difficulties compared with husbands who did not participate. Longitudinal data indicated that couples who participated in premarital programs did not have better marital outcomes than couples who did not participate. The present article also addresses the need to develop procedures that will increase at-risk couples' participation in premarital programs and to improve the effectiveness of these programs in community settings.

Are premarital prevention programs reaching couples at risk for marital dysfunction?

In 2 studies, newlyweds reported whether they had participated in premarital counseling and provided data on known risk factors for marital dysfunction. Couples who participated in premarital programs were not at greater risk for marital difficulties, and in some cases participating husbands were at lower risk for marital difficulties compared with husbands who did not participate. Longitudinal data indicated that couples who participated in premarital programs did not have better marital outcomes than couples who did not participate. The present article also addresses the need to develop procedures that will increase at-risk couples' participation in premarital programs and to improve the effectiveness of these programs in community settings.

The role of negative affectivity in the association between attributions and marital satisfaction

Structural equation modeling with latent variables was used to test whether negative affectivity, or the cross-situational tendency to experience and express negative thoughts and feelings, correlates with spouses' attributions for relationship events and accounts for the association between attributions and satisfaction. Eighty married couples completed measures of marital satisfaction, attributions, and negative affectivity. Spouses high in negative affectivity tended to make maladaptive attributions, but spouses' attributions were unrelated to the level of negative affectivity reported by the partner. Attributions and marital satisfaction remained associated among husbands and wives after controlling for negative affectivity. These findings clarify the link between attributions and marital satisfaction and raise the possibility that negative affectivity contributes to the attributions that spouses make for negative events in marriage.

The role of negative affectivity in the association between attributions and marital satisfaction

Structural equation modeling with latent variables was used to test whether negative affectivity, or the cross-situational tendency to experience and express negative thoughts and feelings, correlates with spouses' attributions for relationship events and accounts for the association between attributions and satisfaction. Eighty married couples completed measures of marital satisfaction, attributions, and negative affectivity. Spouses high in negative affectivity tended to make maladaptive attributions, but spouses' attributions were unrelated to the level of negative affectivity reported by the partner. Attributions and marital satisfaction remained associated among husbands and wives after controlling for negative affectivity. These findings clarify the link between attributions and marital satisfaction and raise the possibility that negative affectivity contributes to the attributions that spouses make for negative events in marriage.

Psychosocial adjustment of the offspring of psychiatric inpatients: the effect of alcoholic, depressive and schizophrenic parentage

While there is a growing body of literature describing the plight of being the child of a particular diagnostic group of psychiatrically ill parents, little is yet known about the comparable vulnerability of the children of various diagnostic groups.

This study includes data collected on 90 psychiatric inpatients, their spouses and children. For each consecutive admission of fifteen male and fifteen female alcoholics with a child less than age 21, a schizophrenic and a depressive parent were matched by sex, age and time of admission. Data were collected on the parents and their children from the patient's chart and through a structured interview with the spouse. A medical history, Rutter's parental questionnaire on children's behaviour and the Randall-McClure behaviour checklist were filled out on 231 children.

Some of the findings of the study include that the adjustment of the children based on checklist information is not affected by the psychiatric diagnosis of the parents; controlling for sibship size is important in this type of research; the boys of sick fathers score almost two times higher on the checklists compared to the boys of sick mothers. The results argue for the provision of coordinated services between adult and child psychiatry departments for the children of the psychiatrically ill parents.