Helical Type Research Articles

Gold Nanoparticles Decorated with HPLC6-Derived Peptides as a Platform for Ice Recrystallization Inhibition.

In nature, organisms living in extreme environmental conditions produce antifreeze proteins (AFPs) that prevent the growth of ice crystals and depress the freezing point of body fluids. In this study, three different peptides derived from the N-terminal sequence of the helical type I AFP HPLC6, along with a stapled derivative produced via on-resin microwave-assisted copper(I)-catalyzed azide-alkyne cycloaddition, were conjugated to gold nanoparticles. The aim of decorating the surface of the nanoparticles with multiple copies of the peptides was to combine the ice-binding capability of the peptides with the size of a nanoparticle, thus, mimicking the protein bulkiness to enhance the peptide antifreeze activity. Ice recrystallization inhibition experiments on the functionalized gold nanoparticles showed a decrease in the ice crystal growth rates with the stapled conjugate being the most active. Conformational studies indicated a major helical content in the constrained peptide, highlighting the importance of a stable conformation for antifreeze activity. Finally, cytotoxicity tests showed that both the peptides and the nanoparticle constructs were nontoxic. The proposed approach could thus represent the starting point for developing effective strategies for cryopreservation.

Numerical investigation of the simultaneous effect of twisted tape and nanofluid hybrid in shell and spiral tube heat exchanger with a special design

Numerical investigation of the simultaneous effect of twisted tape and nanofluid hybrid in shell and spiral tube heat exchanger with a special design

Operating Characteristics of a Wave-Driven Plasma Thruster for Cutting-Edge Low Earth Orbit Constellations

This paper outlines the development phases of a wave-driven Helicon Plasma Thruster for cutting-edge Low Earth Orbit (LEO) constellations. The two-stage ambipolar electric propulsion (EP) system combines the efficient ionization of an ultra-compact helicon reactor with plasma acceleration based on an ambipolar electric field provided by a magnetic nozzle. This paper reveals maturation challenges associated with an emerging EP system in the hundreds-watt class, followed by outlook strategies. A 3 cm diameter helicon reactor was operated using argon gas under a time-modulated RF power envelope ranging from 250 W to 500 W with a fixed magnetic field strength of 400 G. Magnetically enhanced inductively coupled plasma reactor characteristics based on half-wavelength right helical and Nagoya Type III antennas under capacitive (E-mode), inductive (W-mode), and wave coupling (W-mode) were systematically investigated based on Optical Emission Spectroscopy. The operation characteristics of a wave-heated reactor based on helicon configuration were investigated as a function of different operating parameters. This work demonstrates the ability of two-stage HPT using a compact helicon reactor and a cusped magnetic field to outperform today’s LEO spacecraft propulsion.

Comparative study of dynamic characteristics between a FHAWT and a helical type FVAWT

Comparative study of dynamic characteristics between a FHAWT and a helical type FVAWT

Design and development of a detopping mechanism for onion detopping machine

Onion detopping is one of the unit operations involved in the cultivation of onion crop. Manual onion detopping is time consuming and highly drudgery. Therefore, an onion detopping machine was designed and developed for higher efficiency. An efficient detopping mechanism designed to achieve the maximum performance parameters in terms of detopping efficiency, per cent damage of onion bulbs and capacity of the onion detopping machine. By considering the crop parameters and functional requirement, four types of shearing designs of detopping tool namely, lead screw, square shaft with two cutting edges, square shaft with four cutting edges and helical roller were designed, developed and evaluated. Among four different shearing mechanisms, the helical roller type detopping tool was found to be effective in detopping the onion leaves. The helical roller type detopping tool had a detopping efficiency (98.44±1.07%), per cent damage (2.05±0.45%), conveying efficiency (97.60±1.02 %) and capacity (372.60±13.95 kg/h), respectively

Design and development of a detopping mechanism for onion detopping machine

Onion detopping is one of the unit operations involved in the cultivation of onion crop. Manual onion detopping is time consuming and highly drudgery. Therefore, an onion detopping machine was designed and developed for higher efficiency. An efficient detopping mechanism designed to achieve the maximum performance parameters in terms of detopping efficiency, per cent damage of onion bulbs and capacity of the onion detopping machine. By considering the crop parameters and functional requirement, four types of shearing designs of detopping tool namely, lead screw, square shaft with two cutting edges, square shaft with four cutting edges and helical roller were designed, developed and evaluated. Among four different shearing mechanisms, the helical roller type detopping tool was found to be effective in detopping the onion leaves. The helical roller type detopping tool had a detopping efficiency (98.44±1.07%), per cent damage (2.05±0.45%), conveying efficiency (97.60±1.02 %) and capacity (372.60±13.95 kg/h), respectively

Comparison of Twin Screw Derotation Type Versus Single Helical Blade Type Cephalomedullary Nail in the Management of Unstable Intertrochanteric Fractures.

The intertrochanteric fracture is a frequently occurring fracture, often attributed to osteoporosis in older populations. Recently, there has been a proposal to perform early surgical fixation on elderly patients to facilitate early rehabilitation. This approach has been shown to have a beneficial effect in lowering comorbidities. The study aims to compare the efficacy of the twin screw derotation type cephalomedullary nail with that of the single helical blade type cephalomedullary nail in the management of unstable intertrochanteric fractures. The research sample included patients from the orthopedic outpatient and emergency departments of Adesh Medical College and Hospital,Ambala Cantt, India, who were scheduled for surgery for unstable intertrochanteric femur fractures. The patients were categorized into two groups according to the kind of implant they were given: either a twin screw derotation cephalomedullary nail or a single helical blade cephalomedullary nail. The functional result was evaluated by comparing the modified Harris hip score (HHS). Patients with unstable intertrochanteric fractures, including reverse oblique fractures and fractures with posteromedial comminution, as well as patients who provided consent, were included in this study. Thirteen individuals received treatment with proximal femoral nail antirotation (PFNA2), whereas 19 individuals received treatment with proximal femoral nail (PFN). The mean age in the PFNA2 group was 69.51, whereas the mean age in the PFN group was 70.804. There were three patients in the PFNA2 group and five patients in the PFN group who had a tip apex distance of more than 25 mm. According to the Cleveland index, nine patients in the PFNA2 group and eight patients in the PFN group had an implant location that was not optimum. Four patients in the PFNA2 group and seven patients in the PFN group had a neck shaft angle difference of more than 10° between their undamaged and operated sides. The mean HHS was 74.55 for the PFNA2 group and 69.88 for the PFN group. The PFNA2 group exhibited four problems, whereas the PFN group had five issues. The study found that both implants offer similar functional outcomes, with adherence to specific radiological parameters optimizing results. While both face similar challenges with osteoporosis, there was no notable distinction between them. Notably, the PFNA2 group showed superior outcomes in perioperative morbidity.

Pseudodiproline (Pro-Cyp) Oligomers Fold into Helical Polyproline Type secondary structures.

The synthesis and conformational properties of oligo-proline mimetics composed of dimeric and tetrameric Pro-Cyp constructs linked by a hydroxymethylene unit are reported. Oligomers were studied both in the solid state and in solution, unveiling right-handed helical conformation depending on the configuration of the vicinally substituted trans-cyclopentane carboxylic acid unit (Cyp). Unlike polyproline oligomers, the alternating synthetic Pro-Cyp counterparts are not stabilized by n-π* interactions but rely instead on the steric demands of the extended backbone conformation within the hydroxymethylene-linked Pro-Cyp repeating units.

Characterization of biochemical and optical properties of Nile tilapia (Oreochromis niloticus) corneal collagen

BackgroundCollagen extracted from fish body parts is a promising biological material. It has an important role in many pharmaceutical, medical applications and tissue engineering such as corneal regeneration and stromal replacement. The present work investigates a new trend to extract collagen from the fish cornea, as a prospected substituent of human corneal collagen by characterizing some biochemical and optical properties of the fish corneal collagen.ResultsExamination of the corneal tissue of Nile tilapia; Oreochromis niloticus was conducted using electron microscopy, Fourier transform infrared (FTIR) spectroscopy, UV–visible spectrophotometry, optical properties, and thermal properties. The fish were divided into 10 groups each of which consisted of 5 fish. 2 groups of fish were examined for each technique. Results indicated that the corneal layers of O. niloticus are thin at the center and thicker at the periphery with the stroma consisting of a triple helical structure collagen type I. The fish cornea showed very weak transmission at the UV regions (190 nm) and maximum transmission at the visible regions. The values of transmission (T), reflected light (R) and scattered light (S) were 2.685 mw, 100 × 10−3 mw at 45° and 40 × 10−3 mw, respectively. Consequently, the percentage of absorbed light is 21.76%. The denaturation temperature of the fish corneal stroma is 22.27 °C.ConclusionsThe method for obtaining fish collagen affects the specific properties of collagen and consequently its further uses as a potential biomedical substituent for mammalian collagen. Specification of the fish species and tissue type is crucial in identifying the quality as well as the physical and functional properties of the extracted collagen.

Disentangling optical effects in 3D spiral-like, chiral plasmonic assemblies templated by a dark conglomerate liquid crystal.

Chiral thin films showing electronic and plasmonic circular dichroism (CD) are intensively explored for optoelectronic applications. The most studied chiral organic films are the composites exhibiting a helical geometry, which often causes entanglement of circular optical properties with unwanted linear optical effects (linearly polarized absorption or refraction). This entanglement limits tunability and often translates to a complex optical response. This paper describes chiral films based on dark conglomerate, sponge-like, liquid crystal films, which go beyond the usual helical type geometry, waiving the problem of linear contributions to chiroptical electronic and plasmonic properties. First, we show that purely organic films exhibit high electronic CD and circular birefringence, as studied in detail using Mueller matrix polarimetry. Analogous linear properties are two orders of magnitude lower, highlighting the benefits of using the bi-isotropic dark conglomerate liquid crystal for chiroptical purposes. Next, we show that the liquid crystal can act as a template to guide the assembly of chemically compatible gold nanoparticles into 3D spiral-like assemblies. The Mueller matrix polarimetry measurements confirm that these composites exhibit both electronic and plasmonic circular dichroisms, while nanoparticle presence is not compromising the beneficial optical properties of the matrix.

Notch signaling pathway induces expression of type IV collagen in angiogenesis.

Mural cell adhesion is important for the localization of basement membrane components during angiogenesis, and cell-cell interactions are thought to be critical for basement membrane formation. Type IV collagen, a component of the basement membrane, and non-triple helical type IV collagen α1 chain (NTH α1(IV)) co-localize in the basement membrane of neovascular vessels. However, it remains unclear how type IV collagen and NTH α1(IV) are produced around the basement membrane. In the present study, we developed a de novo angiogenesis model using human umbilical vein endothelial cell spheroids and TIG-1 fibroblast cells and demonstrated that NTH α1(IV), probably with α1(IV) chain before forming triple helix molecule, was localized in the fibroblasts in contact with vascular endothelial cells. This localization was disrupted by DAPT, a Notch signaling inhibitor. DAPT treatment also reduced type IV collagen and NTH α1(IV) secretion in TIG-1 fibroblasts, along with diminished COL4A1 and COL4A2 gene expression. Downregulation of Notch3 in TIG-1 fibroblasts decreased the secretion of type IV collagen and NTH α1(IV). Taken together, these findings suggest that heterogeneous and homogeneous intercellular Notch signaling via Notch3 induces type IV collagen and NTH α1(IV) expression in fibroblasts and contributes to basement membrane formation in neovascular vessels.

Mathematical modeling and comparative analysis of baffle types in heat exchange equipment

The development of digital technologies has significantly increased the effectiveness of production and research, especially in the oil and gas industry, where mathematical modeling plays a significant role in equipment design. This paper presents research aimed at developing digital twins of process equipment and focuses on heat exchangers with different types of baffles. The main focus is on comparing the effectiveness of segmental, helical, spiral and disk-ring type baffles as well as tube finning for heat transfer intensification. Numerical experiments using ANSYS CFX for modeling of hydrodynamics and heat transfer in shell and tube heat exchangers with different baffle designs have been carried out. The results showed that disk-ring baffles provide the highest effectiveness of heat transfer, but lead to inhomogeneous velocity and pressure distributions. Spiral baffles showed a significant improvement in heat transfer with relatively low hydraulic resistance, despite difficulties in fabrication and installation. Segmental baffles remain the most popular due to their simplicity and low cost, while rod baffles require further research due to their low effectiveness and high resistance. The paper concludes by recommending the development of digital twins and their use in equipment design, modernization and operation to select optimal mode parameters and solve structural optimization objectives, which has a positive effect on the effectiveness and reliability of equipment in operation.

Non-Stationary Helical Flows for Incompressible Couple Stress Fluid

We explored here the case of three-dimensional non-stationary flows of helical type for the incompressible couple stress fluid with given Bernoulli-function in the whole space (the Cauchy problem). In our presentation, the case of non-stationary helical flows with constant coefficient of proportionality α between velocity and the curl field of flow is investigated. In the given analysis for this given type of couple stress fluid flows, an absolutely novel class of exact solutions in theoretical hydrodynamics is illuminated. Conditions for the existence of the exact solution for the aforementioned type of flows were obtained, for which non-stationary helical flow with invariant Bernoulli-function satisfying to the Laplace equation was considered. The spatial and time-dependent parts of the pressure field of the fluid flow should be determined via Bernoulli-function if components of the velocity of the flow are already obtained. Analytical and numerical findings are outlined, including outstanding graphical presentations of various types of constructed solutions, in order to elucidate dynamic snapshots that show the timely development of the topological behavior of said solutions.

The effect of alphabet-shaped twisted tape on thermo-fluidic properties in a shell-tube type heat exchanger: A comparative study utilizing a two-phase mixture model

The effect of alphabet-shaped twisted tape on thermo-fluidic properties in a shell-tube type heat exchanger: A comparative study utilizing a two-phase mixture model

Comparative study of functional and radiological outcomes of the usage of two devices, derotation type cephalomedullary nail and the helical blade type in unstable intertrochanteric fractures in the geriatric population at a tertiary-level center

Background: Intertrochanteric fracture is a common osteoporotic fracture among elderly populations in an aging society. Early surgical fixation on these aging patients has been proposed recently for early rehabilitation and has had a positive impact on reducing comorbidities. For unstable fractures, intramedullary implants generally present biomechanical advantages over their extramedullary counterparts. Methods: The study was a 2 years prospective comparative study from 1st December 2020 to 1st December 2022 conducted in the department of orthopaedics, Rajendra institute of medical sciences, Ranchi, Jharkhand, India. Total number of patients were 50, PFN done in 25 cases and PFN-A2 in another 25 cases. Results: Mean age is 64.4 years in PFN group as compared to 67.3 years in PFN-A2 group. PFN-A2 was done in 84% male while PFN in only 76 % male and in both groups right side was mostly affected. Average surgery time, amount of blood loss, average number of C-arm shoot was more in PFN group. Conclusions: In this study of 50 patients, 25 treated by PFN and 25 by PFN-A2, it was concluded that PFN-A2 was a better construct to treat patients of older age group having osteoporosis because here reaming was not done and helical blade was inserted by hammering which caused compaction of bones in head and neck region.

Simulation and Experimental Activity for the Evaluation of the Filling Capability in External Gear Pumps

Partial electrification of hydraulic circuits to achieve energy savings requires an increase in the angular speed of the positive displacement pumps, with the risk of incomplete filling. In this context, the paper focuses on developing a computational fluid dynamics (CFD) model using SimericsMP+ for two external gear pumps, namely helical and spur type gears. The objective of this study is the analysis of the phenomena occurring on the suction side under conditions of incomplete filling at high speeds. Both CFD models have been validated by conducting experimental tests for measuring the flow rate delivered at various inlet pressures and angular speeds. The experimental results confirm the model’s capability to accurately detect the operating conditions at which the delivered flow rate starts to decrease due to the partial filling of the inter-teeth chambers. Furthermore, this paper investigates the effects of certain geometrical modifications to the spur gear pump. Specifically, the influence of the gear’s width-to-diameter ratio is studied, revealing that a lower ratio leads to slightly better filling. Conversely, increasing the inlet port diameter results in no improvement. Based on this study, the modelling approach appears to be accurate enough to serve as design tool for optimizing pumps to improve their filling capability.

Research on the Effect of Burial Depth on The Bearing Characteristics of Three Helical Piles Jacket Foundation for Offshore Wind Turbines

With global offshore wind power gradually moving to deep and distant waters, there is a clear trend towards larger-scale units, posing significant challenges for future offshore wind power foundations. In this paper, a helical pile jacket foundation type is proposed by combining the advantages of the current jacket foundation, which is suitable for deep and distant seas and offers high stiffness, with the excellent bearing performance of helical pile foundations. The influence of buried depth on the bearing characteristics of this foundation type is discussed through a physical model test. The results obtained from the study reveal the distinct bearing characteristics and damage modes exhibited by the foundation under deep and shallow burial conditions. These findings clearly indicate that the overall bearing characteristics and damage modes are superior in deep burial conditions compared to shallow burial conditions. Furthermore, it is observed that the damage and displacement of the foundation are more concentrated in localized areas when subjected to shallow burial.

Development and evaluation of mixing mechanism of new transformable multiple impeller (AM impeller)

AbstractThe axial flow in the vessel was the most critical flow under the laminar region, where the Reynolds number was less than 10. The most popular impeller which generates the axial flow is a helical ribbon impeller, but the production cost is high. By combining some pitched blade impellers, authors developed a new impeller, the production cost is lower than that of the helical ribbon. The mixing performance was investigated in laminar region. The new impeller had the same mixing performance as a helical ribbon. The partial helical ribbon type has a down flow that originates from two locations and intersects twice near the mixing shaft, and the four‐stage pitched paddle type has two cylindrical down flows. AM impeller is not affected by the shaft, and it is considered to exhibit high mixing performance. The phase angle of the blades caused these characteristics of down flows of the AM impeller.

Synthesis of hydrogen bonded copper(II) coordination polymer: Photocatalytic degradation of Rose Bengal dye and luminescent sensing of Hg+2, Cr2O72−, and nitrofurantoin

Synthesis of hydrogen bonded copper(II) coordination polymer: Photocatalytic degradation of Rose Bengal dye and luminescent sensing of Hg+2, Cr2O72−, and nitrofurantoin

SIMULASI BILAH TURBIN ANGIN SUMBU VERTIKAL (VAWT) TIPE ROTOR HELICAL UNTUK PEMBANGKIT LISTRIK TENAGA ANGIN DI TEPI PANTAI BUKIT DAN JALAN

The energy crisis is caused by rapid technological developments throughout the world resulting in increased use of fossil energy and global warming, so it is necessary to develop renewable energy technologies to maintain energy stability in the world. One of the renewable energy potentials is wind energy with a Helical rotor type vertical axis wind turbine using NACA 0021 as the blades, the research method used is the numerical method with the result that the wind speed on the parangtritis beach is 4.74 m/s and the air density is 1.2 Kg/m^3 with the power generated using 4 rotor blades of 59.2 Watt/h. then on the paragliding hill, an air speed of 4.55 m/s and an air density of 1.16 Kg/m^3 is obtained, and on the western Yogyakarta ringroad which has an airspeed of 3.885 m/s and an air density of 1.17 Kg/m^3, it produces an electric power of 31.9 Watt/h. The power results generated between the simulation and manual calculations are not much different, so the power accuracy between the two is quite good.