Increase In Torque Values Research Articles

Energy and exergy analysis with emissions evaluation of a gasoline engine using different fuels

Petroleum-based fuels are used extensively as a result of the rising energy demands. Studies on fuels that will replace these fuels are now ongoing. In this study, performance, emission values of 4 different fuels at 4 different torque values were evaluated, and energy and exergy analyses were done utilizing combinations of gasoline, natural gas, and methanol. The tests employed a Lombardini LGW 523 2-cylinder 4-stroke engine. Four different fuels (gasoline, gasoline plus 50 g of natural gas, M20, and M20 plus 50 g of natural gas) were tested at a constant 3000 rpm with four different torque values (5, 10, 15, 20). In tests, it produced the lowest specific fuel consumption and the best emissions when combined with 50 g of natural gas fuel. The purpose of this study was to show that as torque increased, values for fuel, network, exhaust, absorption water, and energy destruction increased, while rates of lost energy decreased and rates of energy destruction increased. With an increase in torque values, all fuel types’ first and second law efficiencies increased in the energy and exergy analysis. The combination of 50 g/h of natural gas fuel and gasoline produced the best results.

Comparation Study Performance Diesel Engine Using Biodiesel with Secondary Data

Biodiesel is one of the diesel engine fuels with a mixture of fossil fuels with the addition of vegetable oil fuels. Biodiesel is expected to compete with other fossil fuels. The purpose of this research is to get a trend in the performance of Diesel engines by using biodiesel against fossil fuels so as to obtain the characteristics of biodiesel fuels. Conduct a comparative study of each different type of biodiesel. Get an upward or downward trend in biodiesel fuels against fossil fuels so as to obtain the characteristics of biodiesel fuels. Diesel engine performance that is concerned is torque, power, specific fuel consumption. The best diesel engine performance requirements are torque value, power and specific fuel consumption decreases. The method of data collection is done using secondary data from the results of previous studies that have been published. This research uses palm oil, jatropha curcas oil, calophyllum inophyllum oil, gossypium arboretum oil, brassica napus oil, and hevea brasiliensis oil. The best Diesel engine performance is found in B25 jatropha curcas oil biodiesel with an increase in torque value of 6.49%, an increase in power value of 6.49%, and a decrease in the value of specific fuel consumption by 17.78%.

The influence of storage media on early osseointegration of titanium implants

Introduction: Marketing of implants stored in different media other than air could improve implant wettability resulting in a favorable implant bone interface with subsequent optimized early osseointegration. The effect that the different storage media, such as saline, air and argon, have on the early osseointegration of plasma treated, titanium dental implants was investigated and was compared to conventional implants stored in air, in an ovine pelvis model. 96 implants were inserted in the iliac crests of four sheep and tested for osseointegration by comparing insertion torque values and removal torque values at 4 and 6 weeks postinsertion. Twelve implants were inserted in each ovine iliac crest (24 per sheep representing six implants from each experimental group). Saline demonstrated the highest increase in torque values with argon demonstrating a linear decrease. The average percentage gain for each of the storage media at 4 weeks were plasma/air = +2%, plasma/saline = +30.4%, air = +9.6% and plasma/argon = −30.4%. The results were only statistically significant for the saline group at 4 weeks and the argon group at 2 weeks. All storage media demonstrated an initial decrease in torque value of 14.25% at 2 weeks before a strong rise in torque value could be observed. Saline as a storage media has great potential for improving early osseointegration. An interesting observation made was that the majority of the dental implants tend to demonstrate an initial decrease in osseointegration before demonstrating a strong rise in torque values. Further studies are recommended for the periods of 6 and 8 weeks after implant placement. Context: Research protocol. Aims: The purpose of the study was to compare the early osseointegration potential of plasma-enhanced implants stored in different storage mediums, to conventional implant stored in air. Settings and Design: The experiment consisted out of a comparative in vivo pilot study in which the early osseointegration potential of implants stored in four different storage media was compared. These implants were inserted in the iliac crest of four sheep, and the degree of osseointegration of the different groups was compared at 2 and 4 weeks after insertion. The osseointegration potential of the implants was evaluated by measuring and documenting the insertion torque and comparing it to the removal torque values of each implant. Subjects and Methods: A total of 96 (n = 96) dental implants (3.75 mm in diameter and 10 mm in length), including 24 plasma-enhanced dental implants stored in air; 24 plasma-enhanced dental implants stored in argon; 24 plasma-enhanced dental implants stored in saline and 24 conventional dental implants stored in air; were inserted into the iliac crests of 4 sheep. The insertion torque values were measured and documented on insertion. Two sheep were euthanized after a period of 2 weeks postinsertion, and the maximum removal torque value of each implant was measured and documented. The remaining two sheep were euthanized at 4 weeks postinsertion and the maximum removal torque of each implant measured and documented. The torque values measured on insertion, after 2 weeks, and after 4 weeks postinsertion were then compared and used to determine the level of osseointegration as well as the potential for further osseointegration. Statistical Analysis Used: Comparative graphical analysis was performed. Significance was determinant at P Results: Saline demonstrated the highest increase in torque values with argon demonstrating a linear decrease. The average percentage gain for each of the storage media at 4 weeks were plasma/air = +2%, plasma/saline = +30.4%, air= +9.6%, and plasma/argon = −30.4%. The results were only statistically significant for the saline group at 4 weeks and the air group at 2 weeks. All storage media demonstrated an initial decrease in torque value of 14.25% at 2 weeks before a strong rise in torque value could be observed. Conclusion: Saline as a storage media has great potential for improving early osseointegration. The majority of the dental implants tend to demonstrate an initial decrease in osseointegration before demonstrating a strong rise in torque values. Further studies are recommended for periods of 6 and 8 weeks after implant placement.

Bacterial Colonization of the Implant–Abutment Interface Using an In Vitro Dynamic Loading Model

Previously, we demonstrated that the geometry of the fixture-abutment interface influences the risk of bacterial invasion into the internal part of the implant, although the contribution of loading on this invasion was not evaluated. The aim of the present study is to use an in vitro dynamic-loading model to assess the potential risk for invasion of oral microorganisms into the fixture-abutment interface microgap of dental implants with different fixture-abutment connection characteristics. Twenty-eight implants were divided into two groups (n = 14 per group) based on their microgap dynamics. Group 1 was comprised of fixtures with internal Morse-taper connection that connected to standard abutments. Group 2 was comprised of implants with a four-groove conical internal connection that connected to multibase abutments. The specimens were immersed in a bacterial solution of Escherichia coli and loaded with 500,000 cycles of 15 N in a wear simulator. After disconnection of fixtures and abutments, microbial samples were taken from the threaded portion of the abutment, plated, and cultured under appropriate conditions. The difference between loosening and tightening torque value was also measured. One of the 14 samples in Group 1 and 12 of the 14 of samples in Group 2 developed multiple colony forming units for E. coli. Implants in Group 1 exhibited an increase in torque value in contrast to implants in Group 2, which exhibited a decrease. This study indicates that differences in implant design may affect the potential risk for invasion of oral microorganisms into the fixture-abutment interface microgap under dynamic-loading conditions.

In vivo bone response and mechanical evaluation of electrosprayed CaP nanoparticle coatings using the iliac crest of goats as an implantation model

Recent trends in clinical implantology include the use of endosseous dental implant surfaces embellished with nano-sized modifications. The current study was initiated to evaluate the mechanical properties, as well as the potential beneficial effects, of electrosprayed CaP nanoparticle-coated (nano-CaP) implants on the in vivo osteogenic response, compared with grit-blasted, acid-etched (GAE) implant surfaces as controls. For this purpose nano-CaP coatings were deposited on cylindrical screw-type (St) implants and implanted bilaterally into the iliac crest of goats for 6 weeks. In addition to histological and histomorphometrical analyses, insertion torque and removal torque values were measured on implant placement and retrieval, respectively. The present study showed similar insertion and removal torque values for nano-CaP-coated and GAE control implants, with no statistically significant increase in torque value during the implant period for either group. With regard to bone–implant contact and peri-implant bone volume, no significant differences were found between nano-CaP-coated and GAE implants after 6 weeks implantation. In conclusion, this study has demonstrated that in situations in which implants are placed in a non-compromised situation using a standard press fit implantation strategy the performance of electrosprayed nano-CaP coatings is comparable with GAE implants, both with respect to implant fixation and bone healing response.

Biomechanical, histological, and ultrastructural analyses of laser micro‐ and nano‐structured titanium alloy implants: A study in rabbit

The aim of this study was to evaluate the biomechanical properties and ultrastructure of the bone response of partly laser-modified Ti6Al4V implants compared with turned, machined implants after 8 weeks in rabbit. The surface analyses performed with interference microscopy and electron microscopy showed increased surface topography with micro- and nano-sized surface features as well as increased oxide thickness of the modified surface. The biomechanical testing demonstrated a 270% increase in torque value for the surface modified implants compared with the control implants. Histological evaluation of ground sections of specimens subjected to biomechanical testing revealed ongoing bone formation and remodeling. A histological feature exclusively observed at the laser-modified surface was the presence of fracture in the mineralized bone rather than at the interface between the bone and implant. Transmission electron microscopy (TEM) was performed on Focused Ion Beam (FIB) prepared samples of the intact bone-implant interface, demonstrating a direct contact between nanocrystalline hydroxyapatite and the oxide of the laser-modified implant surface. In conclusion, laser-modified titanium alloy implants have significantly stronger bone anchorage compared with machined implants and show no adverse tissue reactions.

A Novel Strategy for the Preparation of Reactively Compatibilized Polymer Blends with Oligomers Containing α‐Methyl Styrene Units

AbstractA novel strategy to prepare reactively compatibilized polymer blends is reported. An oligomer that consists of AMS (α‐methyl styrene) and GMA (glycidyl methacrylate) is initially synthesized. When this oligomer is melt blended with poly(propylene) (PP), the GMA units in the oligomer are successfully grafted onto the PP chain, which is proven by measuring the FT‐IR spectrum of the blended PP. When the oligomer is added to a blend of PP/Ny66, an in‐situ compatibilization occurs, which leads to an increase in torque values during blending, a decrease in crystallinity degree of Ny66, and is observed by SEM images of the resulting blends. The compatibilizing effects of the oligomer are also observed in PP/Ny6 and polyethylene/Ny6 blends. A relevant compatibilization mechanism is proposed.magnified image

Histologic Evaluation of Implants Following Flapless and Flapped Surgery: A Study in Canines

Flapless surgery requires penetration of the alveolar mucosa and bone without reflection of mucoperiosteal flaps. Do these techniques force gingival tissue or foreign materials into osteotomies? If so, do such tissues or materials interfere with osseointegration? A proof-of-principle study using a canine model attempted to answer these questions. Five young adult Hound Labrador mongrel dogs received implants with a moderately roughened surface by anodic oxidation using flapless or conventional one-stage (control) surgery in contralateral jaw quadrants. The implants were placed into the osteotomies, and the international stability quotient (ISQ) was recorded using resonance frequency analysis. These measurements were repeated following a 3-month healing interval when the animals were euthanized, and implants and surrounding tissues were retrieved and processed for histologic analysis. The implants were stable upon insertion and demonstrated increased stability at 3 months without significant differences between surgical protocols. The histologic evaluation showed high bone-implant contact (flapless surgery: 54.7% +/- 8.4%; control: 52.2% +/- 13.0%; P >0.05) without evidence of gingival tissue or foreign body inclusions. There were no significant differences in marginal bone levels between the surgical protocols. Post-insertion and at 3 months, ISQ values depended on the amount of torque delivered. Immediately post-insertion, for every 1-unit increase in torque value, the ISQ increased by 0.3 (95% confidence interval: 0.1 to 0.4; P = 0.0043). Three months postoperatively, for every one-unit increase in torque the ISQ value decreased 0.2 (95% confidence interval: -0.4 to -0.1; P = 0.0012). The effect of torque on ISQ values was independent of treatment effects and remained significant after adjustment for treatment. The results suggest that implants placed without flap reflection remain stable and exhibit clinically relevant osseointegration similar to when implants are placed with flapped procedures. Greater torque at implant placement resulted in less implant stability at 3 months.

Ethylene/propylene/5-ethylidene-2-norbornene

Ethylene/propylene/5-ethylidene-2-norbornene(ENB) terpolymerization was carried out with a highly active Ti catalyst system(MgCl2/TiCl4/C6H5COOC2H5 (EB) — AliBu3/di-iso-amyl ether (IAE)). The obtained terpolymer could be vulcanized with sulfur, but the increase of torque value through the vulcanization measured by curelastometer for the terpolymer obtained with this catalyst was considerably lower than that for the terpolymer obtained with the conventional VOCl3 catalyst system. It was suggested that lower torque value would be attributed to the heterogeneous diene distribution in the obtained terpolymer, particularly lower ENB content in the high molecular weight fraction.