The bifunctional formalism: an alternative treatment of density functionals

The bifunctional formalism presents an alternative how to obtain the functional value from its functional derivative by exploiting homogeneous density scaling. In the bifunctional formalism the density dependence of the functional derivative is suppressed. Consequently, those derivatives have to be treated as formal functional derivatives. For a pointwise correspondence between the true and the formal functional derivative, the bifunctional expression yields the same value as the density functional. Within the bifunctional formalism the functional value can directly be obtained from its derivative (while the functional itself remains unknown). Since functional derivatives are up to a constant uniquely defined, this approach allows for a pointwise comparison between approximate potentials and reference potentials. This aspect is especially important in the field of orbital-free density functional theory, where the burden is to approximate the kinetic energy. Since in the bifunctional approach the potential is approximated directly, full control is given over the latter, and consequently over the final electron densities obtained from variational procedure. Besides the bifunctional formalism itself another concept is introduced, dividing the total non-interacting kinetic energy into a known functional part and a remainder, called Pauli kinetic energy. Only the remainder requires further approximations. For practical purposes sufficiently accurate Pauli potentials for application on atoms, molecular and solid-state systems are presented.

Characteristics of Abs and Pla Material in 3D Printing for Car Backseat Headrest Hanger/Hook Model

Additive manufacturing (AM) is known as the technology which enable using a layer wise in fabrication of a complex part directly from CAD files without using any specific tooling. This manufacturing techniques offers many strategic advantages which include design freedom for the build of complex part geometries which cannot be made in other way, the ability to build functional part in a small size for the end user customization and its ability to do improvement for the expensive part in aerospace and other industries. The aim of this research is to study the effect of process parameter such as layer thickness, infill density and object orientation to the accuracy of printed part measurement with CAD model, surface roughness and mechanical strength of PLA and ABS material. Therefore, it is important to find the optimum value of dimensional accuracy, surface roughness and mechanical strength for both materials. To achieve the optimum value of dimensional accuracy, surface roughness and mechanical strength for both materials, Taguchi method L4 orthogonal array is used to conduct this experiment and Minitab 18 software will analyze the result and shows the best optimum value. The result from ANOVA analysis shows that object orientation gives highest contribution to the dimensional accuracy and surface roughness for both materials. Meanwhile, for mechanical strength layer thickness highly contributed to the ABS material and object orientation for the PLA material. A Car Backseat Headrest Hanger/Hook model is fabricated by the best optimal combination and level of process parameter of mechanical strength.

Fracture toughness of ABS additively manufactured by FDM process

Purpose: The purpose on this article is to study the failure of FDM printed ABS by exhibiting an exhaustive crack growth analysis mainly based on raster angle parameter. Design/methodology/approach: Two approaches have been developed in this study; On one hand, mechanical experiments were carried out to determine the critical stress intensity factor KIC. On the other hand, numerical analysis was used to predict the paths within the part as well as the crack propagation. Findings: This work has clearly shown the effect of raster angle on the damage mechanism of the ABS printed by FDM. Indeed, for the combination 1 (0°/90°), the structure presents an important stiffness and a high degree of stress distribution symmetry with respect to the notch. Moreover, the crack propagation is regular and straight, and the damage surfaces are on the same plane. However, for the combination 2 (-45°/45°), the structure is less resistant with an asymmetrical stress distribution according to two different planes. Research limitations/implications: In order to present an exhaustive study, we focused on the effect of two raster angles (including 0°/90°, -45°/45°) on the ABS crack propagation, additively manufactured. This study is still in progress for other raster angles, and will be developed from a design of experiments (DoE) design that incorporates all relevant factors. To highlight more the cracking mechanisms, microscopic observations will be developed in more depth. Practical implications: Our analysis can be used as a decision aid in the design of FDM parts. Indeed, we can choose the raster angle that would ensure the desired crack propagation resistance for a functional part. Originality/value: In this article, we have analyzed the mechanism of damage and crack propagation. This topic represents a new orientation for many research papers. For our study, we accompanied our experimental approach with an original numerical approach. In this numerical approach, we were able to mesh distinctly raster by raster for all layers.

Simulating the Climatic Impact on Vehicle Engine Function Parts

The paper describes the assessment of the influence of climatic conditions, temperature and relative humidity on the lifespan of the cylinder forming the functional part of the vehicle TATRA 815 6x6 VVN. Based on the measured notch-toughness value in the test temperature range -80 °C to +100 °C, the corrosion effect on specimens with and without corrosion protection was evaluated. A condensation chamber was used to simulate corrosion conditions which can cause corrosion and degradation process in the material leading to lifetime reduction and limit state development. The duration of the corrosion laboratory tests in the condensation chamber considered the real time when the TATRA 815 6x6 VVN vehicle is exposed to climate change on an open area in the fleet. There were three sets of samples for simulations with different number of cycles (9, 18 and 27 cycles).

Development of modular wrist, hand and finger orthesis by additive manufacturing

Additive Manufacturing (AM) has been considered an innovative technology for the development of orthoses. Even so, the use of AM, utilizing low cost rigid and flexible material which can be used in different ways by the same user, to produce a modular orthosis has yet to be explored. Purpose: Develop a modular wrist, hand and finger orthosis that can be utilized as a functional or static orthosis, depending on the therapeutic objective. This being produced by low cost Additive Manufacturing, through a single anatomy acquisition process. Approach: Firstly, requirements for modularization and development were defined in a team with occupational therapists and mechanical engineers, After indirect anatomy acquisition of a volunteer, without disabilities, two parts of the same orthosis were modeled, one flexible (functional) and the other rigid (static). These were printed on PLA (rigid part) and flexible TPU (functional part) with an Open Source printer. In addition, fastening strips were also made in flexible TPU. Findings: Three parts of which make up the modular orthosis were produced. This can be used in two different ways; one being to maintain the static posture of the wrist, hand and fingers and the other to provide functionality of the hands, but with the correct positioning of the wrist and thumb. Originality: Even with low-cost material and an open source machine, it was possible to generate an innovative proposal with the use of AM as the orthosis manufacturing process.

A review of recently developed polymer composite materials for fused deposition modeling 3D printing

Additive Manufacturing (AM) is a rapidly evolving technology due to its numerous advantages over traditional manufacturing processes. AM processable materials are limited and have poor mechanical performance, restraining the technology's potential for functional part manufacturing. Although FDM is the most popular and growing technique, the inferiority of the material limits its application to prototyping. Nanocomposite material improves the thermal, mechanical, and electrical performance of FDM objects. Mostly polymer nanocomposites are feasible to process and several researchers have reported enhanced performance with polymer nanocomposites. Carbon nanotubes, graphene nanoplatelets, nano clay, and carbon fiber are primary reinforcements to thermoplastics. The current state of the art relevant to advances in nanocomposites for the FDM process, as well as the influence of nanofillers on mechanical properties of the build object are reviewed in this paper.

Management of Grahani roga in Ayurveda (irritable bowel syndrome)- A case report

Grahani Roga is a common Gastro-intestinal Tract disorder of present era. In Ayurveda, Grahani is considered as the main functional part of Mahasrota which is located in between amashaya & pakwashaya, also known as the 6th kala i.e., Pittadhara Kala where jatharagni resides and its main function is to hold the ahara upto the end of avasthapaka & after completion passes it into pakvasaya. Symptoms like alternate passing of hard & loose stool, abdominal pain, passing of foul-smelling stool, mucus in faecal matter are diagnostic of Grahani Roga. In modern science, above mentioned symptoms can be correlated with IBS (Irritable Bowel Syndrome). In IBS, the wall of the intestine becomes sensitive to even mild stimulus which causes excess abdominal cramps & hence the bowel movement alters along with indigestion. In this case an effort has been made to treat 33 years male suffering from Grahani roga, at Ayurveda Teaching Hospital within 3 months by various ayurveda medicine and panchakarma procedures.

The 3D Genome: From Structure to Function

The genome is the most functional part of a cell, and genomic contents are organized in a compact three-dimensional (3D) structure. The genome contains millions of nucleotide bases organized in its proper frame. Rapid development in genome sequencing and advanced microscopy techniques have enabled us to understand the 3D spatial organization of the genome. Chromosome capture methods using a ligation approach and the visualization tool of a 3D genome browser have facilitated detailed exploration of the genome. Topologically associated domains (TADs), lamin-associated domains, CCCTC-binding factor domains, cohesin, and chromatin structures are the prominent identified components that encode the 3D structure of the genome. Although TADs are the major contributors to 3D genome organization, they are absent in Arabidopsis. However, a few research groups have reported the presence of TAD-like structures in the plant kingdom.

Symptomatic Oculomotor Nerve Cyst in a 3-Year-Old Child: Case Report With Emphasis on Surgical Management

BACKGROUND AND IMPORTANCE Third nerve palsies in the pediatric population are most commonly caused by trauma, tumors, or vascular abnormalities. Cystic oculomotor nerve neuropathies, however, are rare. We report the case of a symptomatic cyst along and within the oculomotor nerve, which has not been described previously. CLINICAL PRESENTATION Here, we report a case of a 3-yr-old girl presenting with a progressive painless oculomotor nerve palsy. A magnetic resonance imaging revealed a cystic formation along the cisternal and cavernous course of the nerve. Due to lack of alternative treatment options, surgery was offered. Intraoperative direct nerve stimulation allowed for identification of a non-functional part of the cyst wall and open fenestration and biopsy were executed. Histopathology revealed neuritis. Serology was negative for various pathogens. The oculomotor palsy rapidly resolved. At a follow-up 5 yr after surgery, the girl is asymptomatic and the cisternal part of the cyst remains collapsed. CONCLUSION This is the first report of a symptomatic cyst along and within the oculomotor nerve treated effectively with open fenestration and decompression highlighting the importance of intraoperative neuromonitoring in cranial nerve surgery. Uncertainty remains regarding the etiology of this disease.

Loading efficiency of doxorubicin into the micelle-like structures formed by function-spacer-lipid constructs self-assembly depends on constructs’ functional part

Supramolecular self-assemble systems based on neoglycolipids: Galili-Ad-CMG2-Ad-DOPE, A(type2)-Ad-CMG2-Ad-DOPE are studied here and compared with the well-studied Biotin-CMG2-Ad-DOPE, as well as with their combinations with NH2-CMG2-Ad-DOPE. They are function-spacer-lipid constructs with unique structure that allows them to form micelle-like supramers and be stable, what makes them a potential drug nanocarriers. The structural properties of the obtained supramolecular systems are studied depending on their functional part, and the loading efficiency of doxorubicin into the supramers is determined to reveal the influence of the functional part. The resulting supramers were separated from the unbound molecules by dialysis, the nanoparticles morphology were studied by atomic force microscopy, and the loading efficiency was calculated based on spectrophotometry data. The encapsulation of doxorubicin was confirmed based on changes in the size and shape of the supramers, as well as a decrease in the ratio of unbound molecules. According to the loading efficiency calculations, it was estimated that supramers formed by A(type2)-Ad-CMG2-Ad-DOPE are the most efficient nanocarriers with loading efficiency of 82 %. Supramers formed by NH2-CMG2-Ad-DOPE (no functional part) showed 1.5 times less efficiency. Finally, the least efficient carriers are supramers formed by Biotin-CMG2-Ad-DOPE (14%).