Types Of Trays Research Articles

Accuracy of Impression Techniques with Maxillary Angled Implants Using Trays and Multifunctional Guides.

The purpose of this study was to evaluate in vitro the accuracy of different splinting techniques using transfers combined with different tray types. The research group fabricated a maxillary master cast with four implants and a passive metallic bar on this master cast. For the impression techniques, 48 casts were used with six different impression techniques: (1) metal tray with resin splinted transfers, (2) metal tray with metal and resin splinted transfers, (3) plastic tray with resin splinted transfers, (4) plastic tray with metal and resin splinted transfers, (5) multifunctional guide with resin splinted transfers, and (6) multifunctional guide with metal and resin splinted transfers (n = 8) using polyvinyl siloxane impression material. This study used a passive metallic bar to measure the malalignment between the framework and the analogs (A, B, C, and D) in 2D and 3D. The master and experimental casts were scanned with a contact scanner to compare the accuracy in 3D impression techniques. Discrepancies between the analogs were measured in three x-, y-, and z-axes. There was no statistically significant difference (P > .05) between the groups in vertical malalignments (2D). In the 3D evaluation, for the z-axis and combination of xz-axis, plastic tray with metal, and resin splinted transfers (z = 487 μm; xz = 888 μm), there was a statistically significant difference compared with the multifunctional guide and resin splinted transfers (z = 772 μm; xz = 1,380 μm). When analyzing by analog, in C, the multifunctional guide with metal and resin splinted transfers (302 μm) presented a statistically significant difference compared with the multifunctional guide and resin splinted transfers (492 μm). The evaluation methods for the accuracy impression technique presented different results between them. There was no difference in vertical malalignments (2D), but in 3D, the bonding with metal and acrylic resin presented better results than the bond with only acrylic resin when using the plastic tray and multifunctional guide, respectively, in the z-axis and the combination between the xz-axes. The bonding technique of the transfers with metal and acrylic resin presents better results in the 3D analysis for the multifunctional guide impressions.

Productivity and quality of sweet potato roots propagated by mini-cuttings with different trays and seedling ages

ABSTRACT The use of mini-cuttings is an option for obtaining sweet potato propagules of excellent quality. The objective of this research was to evaluate the production and quality of sweet potato roots propagated by mini-cuttings in different types of trays and ages of seedlings. Six treatments, resulting from the factorial 2x3, were evaluated: two types of trays (162 and 200 cells, with 31 and 18 mL of substrate per cell, respectively) and three ages of seedlings (39, 46 and 53 days after placement of mini-cuttings in trays), in a randomized block design, with five replications. Seedlings characteristics, production and quality of roots were evaluated. Higher number and dry weight of leaves per seedling were observed in the tray with 162 cells than in trays with 200 cells. The younger seedlings (39 days) had a lower number of leaves, dry weight of leaves, stem, roots ant total (leaves + stem + roots) than seedlings of other ages. There was no difference in root production depending on the type of tray, regardless of the age of the seedlings. For the 162-cell tray, the age of the seedlings did not affect the production of roots. On the other hand, for the 200-cell tray, higher roots production was observed on seedlings 39 days age compared to seedlings with 53 days. No differences were observed among the roots of different treatments for titratable acidity, and levels of sucrose, reducing sugars ant total sugars. It is recommended to avoid old seedlings, that is, it is recommended to use seedlings with a maximum of 43 days after planting of mini-cuttings for trays with 200 cells, while for trays with 162 cells no difference in root production was observed with the different ages of the seedlings.

Towards Sustainable Concrete Composites through Waste Valorisation of Plastic Food Trays as Low-Cost Fibrous Materials

Recycling of waste plastics is an essential phase towards cleaner production and circular economy. Plastics in different forms, which are non-biodegradable polymers, have become an indispensable ingredient of human life. The rapid growth of the world population has led to increased demand for commodity plastics such as food packaging. Therefore, to avert environment pollution with plastic wastes, sufficient management to recycle this waste is vital. In this study, experimental investigations and statistical analysis were conducted to assess the feasibility of polypropylene type of waste plastic food tray (WPFT) as fibrous materials on the mechanical and impact resistance of concrete composites. The WPFT fibres with a length of 20 mm were used at dosages of 0–1% in two groups of concrete with 100% ordinary Portland cement (OPC) and 30% palm oil fuel ash (POFA) as partial cement replacement. The results revealed that WPFT fibres had an adverse effect on the workability and compressive strength of concrete mixes. Despite a slight reduction in compressive strength of concrete mixtures, tensile and flexural strengths significantly enhanced up to 25% with the addition of WPFT fibres. The impact resistance and energy absorption values of concrete specimens reinforced with 1% WPFT fibres were found to be about 7.5 times higher than those of plain concrete mix. The utilisation of waste plastic food trays in the production of concrete makes it low-cost and aids in decreasing waste discarding harms. The development of new construction materials using WPFT is significant to the environment and construction industry.

Accuracy and feasibility of 3D-printed custom open trays for impressions of multiple implants: A self-controlled clinical trial

Statement of problemThree-dimensionally printed custom open trays have become a popular option in clinical implant dentistry because of advantages such as individualization, efficiency, and effectiveness. However, clinical evidence on their accuracy and feasibility is lacking. PurposeThe purpose of this clinical study was to evaluate the accuracy and feasibility for impressions of multiple implants by using 3D-printed custom open trays versus conventional custom open trays. Material and methodsTwenty-two partially edentulous individuals needing impression making for restorations supported by multiple implants were enrolled. Two types of custom open trays were made for each participant, a 3D-printed tray (test) and a conventional tray (control). With a splinted technique, silicone definitive impressions were obtained with the 2 custom open trays and poured with Type IV dental stone. Impression accuracy (primary outcome) was evaluated by measuring linear distances and the marginal gaps between the implant replicas and verification devices on the test and control casts. Clinical tray fit, impression quality, and cast quality were rated by an independent technician through a visual analog scale (VAS). The fabrication time and cost of the 2 types of custom open trays were recorded. The feasibility of 3D-printed trays was determined from these outcomes. The paired Student t test and Wilcoxon rank-sum tests were used for statistical analysis (α=.05). ResultsFor impression accuracy, no statistically significant difference was found between test and control groups (P>.05). In terms of clinical tray fit, impression quality, and cast quality, no statistically significant difference was found (all P>.05). Regarding fabrication time and cost, the test group (57.65 ±6.49 minutes, 0.37 ±0.07 United States dollars [USD]) exhibited superiority over the control group (101.96 ±2.92 minutes, 4.41 ±0.37 USD) (both P<.001). ConclusionsWithin the limitations of this study, the 3D-printed custom open trays were clinically accurate, efficient, and cost-effective for impressions of multiple implants.

A novel active-mode indirect solar dryer for agricultural products: Experimental evaluation and economic feasibility

This article presents a novel active-mode indirect solar dryer consisting of highly efficiency through-flow evacuated tube collector for air heating. A DC fan powered with solar photovoltaic (PV) module is provided for forced air flow through this dryer. The dehydration chamber is of tray type with loading capacity of 6 kg–45 kg depending on the drying product. The dryer was evaluated to dry fenugreek leaves (Trigonella foenum-graecum) and turmeric (Curcuma longa) in semi-continuous mode; and respective overall thermal efficiency was found to be 34.1% and 23.6%. The respective thermal efficiency in open sun drying (OSD) was 5.7% and 5.4%. The quality of dried fenugreek leaves and turmeric was found better than OSD. Economics of the solar dryer indicate the capital cost is negligible in comparison to cumulative present worth of life cycle savings. The values are 211,262 INR (1 US$ = 74.57 INR) and 229,152 INR respectively for fenugreek leaves and turmeric; and capital cost of the dryer is only 50,000 INR. The low value of payback period also confirms economic viability of this dryer. The generalized economic curves have also been plotted.

Modified impression technique for patient with microstomia

Routine custom trays are difficult to use to make impressions for patients with microstomia. Several types of split custom trays have been introduced to accommodate these situations. A method of fabricating mandibular and maxillary sectional special trays and impression technique for a patient with small oral opening is described. Sectional maxillary and mandibular custom trays can enhance its stabilization during border molding and final impression making. Thus it helps in fabricating a better fitting complete denture for such patients and also makes the impression procedure easy for patient with limited opening as the tray can easily be inserted in two pieces. Keywords: Impression, Microstomia, Sectional custom tray.

Evaluation of the quality of fixed prosthesis impressions in private laboratories in a sample from Yemen

BackgroundFixed prosthodontics require an accurate impression for the teeth and the area to be restored for the laboratory to fabricate the desired restoration without mistakes. This study evaluated the quality of impressions received by private laboratories for the fabrication of fixed prosthesis by describing the frequency of clinically detectable errors and by analyzing association between the various factors involved.Methods165 impressions were collected from four dental laboratories. Jaw involved, type of tray, size of tray, number of prepared units, type of impression materials, techniques and viscosity in case of elastomeric impressions and type of prosthesis requested were recorded. Data referring to errors and visible defects including errors in finish line, in preparation area, in silicone impression technique and blood in impression were also documented. Factors affecting errors present were also assessed. Association between dentist gender and experience years and impression errors was assessed. Chi square and Fisher exact tests used to examine the association between categorical variables and outcomes.ResultsThe total of error considering not immediately pouring as an error. Alginate was the most impression used. of impressions evaluated (50.9%), 97% were have at least one visible error; 92.1% had errors in finish line, 53.9% had errors in preparation area and (72.8%) of elastomeric impressions were have at least one error in technique. Blood in impression was detected in 52.1% of impressions. Significant association was found between material type and errors in finishing line and preparation area. Significant relationships were found between gender and errors in silicone impression technique (p < 0.05).ConclusionWithin the limitations of this study, high frequency of detectable errors was found in fixed prosthesis impressions received by private dental laboratories. This high frequency is of serious concern, as this will result in poor fitted fixed prosthesis provided to patients.

Development of tray type nursery seeding equipment

In India, near about 70% people are dependent upon agriculture. So the agricultural system in India should be advanced to reduce the efforts of farmers. Various numbers of operations are performed in the agriculture field like seed sowing, weeding, cutting, pesticide spraying etc. Very basic and significant operation is seed sowing. But the present methods of seed sowing are problematic because the equipment used for seed sowing are very difficult and inconvenient to handle. So there is a need to develop equipment which will reduce the efforts of farmers. This system introduces a control mechanism which aims to drop seeds at particular position with specified distance between two seeds and lines while sowing. The drawbacks of the existing sowing machine will be removed successfully in this automatic machine. Multiple operation can be done easily and no need of labours and no need of wages to be given to the labours. Energy of the farmers will be gained. Time consumption is much less than any other equipment.

Comparison of the transfer accuracy of two digital indirect bonding trays for labial bracket bonding.

To compare the transfer accuracy of two digital transfer trays, the three-dimensional printed (3D printed) tray and the vacuum-formed tray, in the indirect bonding of labial brackets. Ten digital dental models were constructed by oral scans using an optical scanning system. 3D printed trays and vacuum-formed trays were obtained through the 3Shape indirect bonding system and rapid prototyping technology (10 in each group). Then labial brackets were transferred to 3D printed models, and the models with final bracket positioning were scanned. Linear (mesiodistal, vertical, buccolingual) and angular (angulation, torque, rotation) transfer errors were measured using GOM Inspect software. The mean transfer errors and prevalence of clinically acceptable errors (linear errors of ≤0.5 mm and angular errors of ≤2°) of two digital trays were compared using the Mann-Whitney U-test and the Chi-square test, respectively. The 3D printed tray had a lower mean mesiodistal transfer error (P < .01) and a higher prevalence of rotation error within the limit of 2° (P = .03) than did the vacuum-formed tray. Linear errors within 0.5 mm were higher than 90% for both groups, while torque errors within 2° were lowest at 50.9% and 52.9% for the 3D printed tray and vacuum-formed tray, respectively. Both groups had a directional bias toward the occlusal, mesial, and buccal. The 3D printed tray generally scored better in terms of transfer accuracy than did the vacuum-formed tray. Both types of trays had better linear control than angular control of brackets.

Types of Impression Trays and its Effect on Impression Materials Choosing.

A dental impression is a negative print of teeth and soft tissues in the mouth which can produce a positive copy model. It can be made by putting a suitable material in a stock or custom dental impression tray which is designed to fit as possible over the dental arches. Figure 1 shows a dental impression made using alginate impression material [1].

Optimisation of the use of resources in the process of production of meals in a maternity hospital according the lens of cleaner production

This research aimed to evaluate the use of resources in the meal distribution process at the nutrition sector of a maternity hospital, with a focus on reducing waste. This was carried out based on the cleaner production (CP) methodology (CNTL, 2003). The scope of evaluation took into consideration the internal food transportation and the use of the natural resources in the process of cleaning trays and utensils (washing and disinfecting trays). In addition, conservation aspects of the served food (food temperature) according to the three types of trays used by the hospital were considered. The evaluation allowed the choice of one of the three trays used according to the mentioned criteria, adding knowledge to the food safety field and to the diversity of the CP methodology implementation in a service company. The existence of standardised and well-defined routines and the support of top management were also success factors for the entire process of diagnosis, presentation of results and implementation of measures (e.g. Standard operational procedures and tray). However, further studies are needed regarding the use of natural resources and impacts generated by the activities of the hospital's kitchen, and more continuous use of the tray that performs better in the aspects studied.

Challenge to enhance the value of the Cameroonian coastal earth: physical tests and mechanical characterization of earth material

One of the main performances of earth material is the thermal regulation. The aim of this study is centered on the possibility of applying the grunge of the Cameroonian Coast for its suitable valorisation. Thus focusing on the parliamentary law so as to be capable of supplying, first, a material with a reduced polluting impact and secondly one with which the thermal comfort of the building would be amended; all these for the population of the Cameroonian Coast. The identification results assure the possibility of using the earth of the Cameroon coastal region for CEB with a grain size distribution even though the crater spindle contained shows a discontinuous tray type. Again, this study aims at showing the possibility of using this earth material for the manufacturing of porcelain, sanitary ware and tableware. As far as the characteristics are concerned, a convergence of the grading, mineralogical and chemical results show a medium-active kaolinite-type clay and a sandy loamy-clay earth. That's why for in-depth knowledge major elements and minerals have been identified by X-ray fluorescence and X-ray diffraction. The mechanical tests carried out on the clay show a sufficient plasticity in the wet state, even though it is also pointing out possibilities of improving these performances by using adequate stabilizers.

Assessment of accuracy of open tray and closed tray dental implant impression techniques: A comparative study

Background: A dental impression is a negative imprint of an oral structure utilized to produce a positive replica of the structure that can be used as a permanent record or in the production process of a dental restoration. Hence; the present study was undertaken for assessing the accuracy of two different dental implant impression techniques. Materials & methods: For reference model, an edentulous mandibular cast with four implant analogues in the anterior region was used. For the present study, two different types of impression trays were used as follows: Closed custom tray, and Open custom tray. The impressions were allowed to set for 10 minutes under a standard load of 500 gm. All the impressions were poured using the same quantity of Type IV dental stone. The casts were subjected to measurement after 24 hours to simulate clinical situation. All the results were recorded in Microsoft excel sheet and were analysed by SPSS software.Results: Mean error obtained in closed custom tray technique was 0.028 while mean error obtained in open custom tray technique was 0.23. While analysing statistically, significant results were obtained. Conclusion: Better results are obtained when open custom trays were used.

Reação de plântulas de melancia forrageira aos ambientes aberto e protegido

Destacada no semiárido nordestino como uma planta de excepcional capacidade forrageira e notória resistência às adversidades do local, a melancia forrageira (Citrulus lanatus cv. Citroides) é mais uma espécie cujo pouco conhecimento a limita como alternativa comercial. A pesquisa foi conduzida na área experimental da Universidade Federal do Piauí, em Teresina, no período de junho a agosto de 2019, e teve como objetivo identificar as reações das plantas em ambiente aberto e protegido, conduzidas em bandejas de poliestireno expandido. O desenho experimental foi feito em blocos casualizados com 4 repetições e os tratamentos em arranjo fatorial 2x2, com os fatores tipo de bandeja (72 e 128 células) e ambiente (céu aberto e cultivo protegido). As bandejas foram preenchidas com substrato comercial e adubação química, distribuídas em suportes a céu aberto e dentro de uma unidade de cultivo protegido com 50% de sombreamento. Para aferir as respostas, foram avaliados os parâmetros: altura da plântula do colo à gema terminal, comprimento da raiz, peso da matéria fresca da parte aérea e das folhas cotiledonares, sendo possível concluir que: as plântulas reagem mais ao tipo de bandeja do que ao ambiente de cultivo, onde bandejas maiores (72 células) influenciam positivamente no peso das folhas cotiledonares, no número de folhas e no peso da matéria fresca da parte aérea. Tanto ambiente quanto o tipo de bandeja interfere no comprimento da raiz, ficando mais profunda nas unidades de 72 células e ambiente aberto e, independentemente do tipo de bandeja, será mais comprida no ambiente aberto.

Seeding soils and tray types mediate growth characteristics of perilla seedlings.

Seeding soils and tray types mediate growth characteristics of perilla seedlings.

Hydrodynamics of the vortex tray

The article presents geometry, dimensions and structural characteristics of tangential swirlers of different design for vortex plates, which are a new type of centrifugal tray. The results of hydraulic tests of the vortex plate with tangential swirlers for an air–water system are given. The research allowed determining the flow regimes of the gas–liquid mixture at the tray and presenting the dependence for determining the critical gas velocity in the channels of the device characterizing the transition from the bubbling flow regime to the annular one. The dependences for calculating the coefficient of hydraulic resistance of the dry tray and the total resistance are determined. The gas content in the rotating liquid layer was studied with determination of the design parameters of the device that affect its value. The values of the angular velocity of the gas–liquid layer are established. The height of the rotating gas–liquid layer is determined and the equation for its calculation is presented. The medium-surface diameter of the gas bubbles in the liquid in the annular flow was 2–3 mm and the interfacial area of the gas–liquid layer was calculated as 600–1,200 m−1.

Investigation of the movement of charge materials in the tray-distributor of the cone-free loading device of the blast furnace

Objective.Determine the analytical dependence of the profile of granular materials moving on the tray-distributor of the cone-free loading device on the length coordinate. Method. Kinematic and geometrical regularities of movement of charge materials on the distributive body of the cone - free loading device of tray type are considered. It is shown that the dynamics of the flow of charge materials is significantly influenced by such factors as the value of the average particle diameter of the loaded material, physical and mechanical characteristics of the charge, its flow rate, angular velocity of the distributor tray and its angle. Results. The analysis of the obtained results makes it possible to calculate with sufficient accuracy the rate of charge rise from the tray-distributor in the furnace space of the blast furnace. This makes it possible to calculate the trajectory of the charge flow in the furnace space and to obtain the coordinate of the intersection of the trajectory with the surface of the charge backfill on the blast furnace grate. The obtained equation of the profile of the movement of charge materials on the tray-distributor makes it possible to recommend the position of the tray when loading the blast furnace, which prevents the transfer of the charge through the edge of the tray. Scientific novelty. A new method for solving the Cauchy problem for a differential equation describing the flow of a charge through a distributor tray is proposed. It is established that the change in the flow rate of charge materials passing through the tray-distributor significantly affects the configuration of the surface of the charge on the tray, and this, in turn, causes a change in the rate of flow into the furnace space. Studies have shown that the motion parameters are significantly affected by the initial height of the charge materials on the tray. Practical significance. The obtained results allow analytical calculation of the change in the dynamics of the charge movement under the condition of a constant angle of inclination of the tray of the loading device of the blast furnace. This makes it possible to expand the possibilities of automatic correction of the gas dynamics of the blast furnace zone in specific charge conditions.

Experimental and Computational Fluid Dynamics Validation of Correlations for Dry Pressure Drop in Trays without Downcomer

AbstractThe dry tray pressure drop (ΔPd) is a design parameter that provides preliminary information about the total pressure drop. This work aimed to assess correlations for ΔPd prediction for different types of trays without downcomer and to evaluate the effects of the free area ratio (φ) and the hole diameter (d) on ΔPd. Assessment was performed by comparing results of several correlations with those from an experimentally validated computational fluid dynamics simulation. The study shows that the correlations of Červenka and Kolář, Bennett, Agrawal and Cook, and Stichlmair and Mersmann predicted the dry pressure drop satisfactorily. The correlation of Bennett, Agrawal and Cook can be recommended for the prediction of ΔPd for a wide range of geometries and operation conditions. Also, φ has a higher influence on ΔPd than d.

Aedes aegypti larval development and pupal production in the FAO/IAEA mass-rearing rack and factors influencing sex sorting efficiency.

The production of a large number of mosquitoes of high biological qualities and reliable sex sorting before release are key challenges when applying the sterile insect technique as part of an area-wide integrated pest management approach. There is a need to fully evaluate the production capacity of the equipment developed in order to plan and maintain a daily production level for large-scale operational release activities. This study aimed to evaluate the potential use of the FAO/IAEA larval rearing unit for Aedes aegypti and the subsequent female contamination rate after sex sorting with a Fay–Morlan glass separator. Trays from each rack were tilted and their contents sorted either for each individual tray or after mixing the content of all trays from the rack. The pupal production and the female contamination rate were estimated with respect to day of collection, position of the tray, type of pupae collection, and sorting operator. Results showed significant daily variability of pupal production and female contamination rate, with a high male pupal production level achieved on the second day of collection and estimated female contamination of male pupae reached around 1%. Neither tray position nor type of pupae collection affected the pupal production and female contamination rate. However, the operator had a significant effect on the female contamination rate. These results highlight the need to optimize pupal production at early days of collection and to develop a more effective and automated method of sex separation.

Optimization of BS4 Enzyme production with Different Substrate Thickness and Type of Trays

BS4 enzyme that is produced from solid substrate fermentation (SSF) on coconut cake with Eupenicillium javanicum BS4 in tray bioreactor has been applied as a feed additive. It increases the nutritional value of animal feedstuff. The BS4 production on SSF may be influenced by the better aeration through the perforated trays or by the thinner substrate. The aim of this research is to optimize the production of BS4 with different substrate thicknesses and types of trays. The trial was carried out using a factorial randomized design (2x2x3) with 6 replicates. The first factor was the type of trays: i.e., non-perforated and perforated tray. The second factor was the thickness of the substrate: i.e., 1.5 and 3.0 cm, while the third factor was the duration of fermentation: i.e. 5, and 7 days. The variables observed were moisture content, dry matter loss (DML), mannanase and saccharification activities, soluble protein content, their specific activities, and yield. Statistical analysis showed no interactions between the three factors, but there were interactions between types of trays and substrate thicknesses, as well as type of trays and incubation times on the mannanase activity and yield of mannanase. The results showed that DML was observed on day 7 were around 31.43- 36.89. The highest mannanase activity was observed on the non-perforated tray with 3 cm thickness on day 7. The saccharification activity towards palm kernel meal was better in the non-perforated tray on day 7 but not influenced by The yield value of mannanase and saccharification activities on a non-perforated tray with 3.0 cm thickness on day 7 was also the highest. Based on energy efficiency and the cost of production, it can be concluded that the optimum condition to produce the BS4 enzyme was observed in the non-perforated tray with 3 cm thickness and fermented for 7 days.