Uncovered Ones Research Articles

The effect of storage conditions on the characteristics of various types of biomass

In order to determine optimal conditions for maintaining biomass quality during storage, an analysis was conducted to investigate the changes in biomass characteristics in Bangkok, Thailand. The study focused on three types of biomass: corncob, woodchip, and bagasse, which are valuable renewable energy resources in the region. Each type of biomass was divided into two separate piles: one covered with a plastic sheet and the other left uncovered. Over a storage period of seven months (February-September), various characteristics of the biomass piles were evaluated, including pile temperature, moisture content, ash content, heating value, and dry matter loss. The findings indicate that the utilization of plastic sheets significantly enhanced the quality of corncob and woodchip biomass. This improvement was attributed to reduced moisture content, leading to higher heating values, lower ash content, and decreased dry matter loss in the covered piles compared to the uncovered ones. However, such improvements were not observed in the case of bagasse, as its quality exhibited fluctuations throughout the study period.

A location-or-routing problem with partial and decaying coverage

This paper studies a generalized location-or-routing problem by considering partial coverage of the users according to a distance-decaying coverage function. In this problem, there is a set of candidate locations where to open facilities, and a set of locations with given number of users that must be covered by the open facilities. Users may travel directly to an open facility if they are within the coverage range of it, or they may be transported to facilities by capacitated vehicles. A distance-decaying function for the facility coverage is considered and the vehicles are allowed to partially cover the users located at the same location. Two mixed integer programming models are presented that minimize the number of uncovered users subject to a restricted budget, and an adaptive large neighborhood search metaheuristic is developed as the solution methodology. Through several computational experiments, the efficiency of the proposed formulations and the solution algorithm are evaluated, and the ALNS algorithm is shown to perform well in terms of solution quality and computing time. Computational results indicate that considering the partial coverage of users reduces the number of uncovered ones as the vehicle capacity decreases, and this reduction is more significant under a distance-decaying facility coverage function. It is also observed that considering distance-decaying coverage increases both the number of uncovered users and the spent budget, especially with a continuous function such as an exponential decay function.

Effect of plastic covering and potassium fertilization source on growth and fruiting of flame seedless grapevines

Grapevine growth and fruiting are affected by covering and potassium fertilization. For two years field study, 2019 and 2020 seasons in a factorial experiment in randomized complete block design were conducted to study the effects of plastic covering and potassium fertilizer sources on Flame Seedless grapevines. Flame Seedless grown in Upper Egypt and harvested between 15th May to 10th June. In this time, market of table grape is suffering from over supply. Thus, prices decrease considerably in the market. On other contrary, harvesting early (before mid of May) leads to at least a 50% increase in the total income. In this experiment outdoor grown Flame Seedless grapevines were covered with UV+IR (Ultra violet + Infra-red) type of polyethylene film (PE) after dormex application at first week of January. Phenological phases like bud-burst, flowering, veraison and ripening as well as vegetative growth, yield quality were determined. Using potassin or feldspar plus potassin significantly increased the growth, and significantly improved the vine nutritional status as well as significantly yield components and improved berry quality. Plastic covering significantly enhanced the dates of all phonological phases, especially ripening that was earlier about 17 & 22 days in both studied seasons compared to uncovered ones. Plastic covering has a positive effect on growth aspects, yield and fruit quality. So, it could be concluded that Flame Seedless grape cultivar gave the highest and earliest yield with good berry quality when covering with plastic film and fertilized with feldspar plus potassin as natural sources of potassium.

Investigating Sentinel 2 Multispectral Imagery Efficiency in Describing Spectral Response of Vineyards Covered with Plastic Sheets

The protection of vineyards with overhead plastic covers is a technique largely applied in table grape growing. As with other crops, remote sensing of vegetation spectral reflectance is a useful tool for improving management even for table grape viticulture. The remote sensing of the spectral signals emitted by vegetation of covered vineyards is currently an open field of investigation, given the intrinsic nature of plastic sheets that can have a strong impact on the reflection from the underlying vegetation. Baring these premises in mind, the aim of the present work was to run preliminary tests on table grape vineyards covered with polyethylene sheets, using Copernicus Sentinel 2 (Level 2A product) free optical data, and compare their spectral response with that of similar uncovered vineyards to assess if a reliable spectral signal is detectable through the plastic cover. Vine phenology, air temperature and shoot growth, were monitored during the 2016 growing cycle. Twenty-four Copernicus Sentinel 2 (S2, Level 2A product) images were used to investigate if, in spite of plastic sheets, vine phenology can be similarly described with and without plastic covers. For this purpose, time series of S2 at-the-ground reflectance calibrated bands and correspondent normalized difference vegetation index (NDVI), modified soil-adjusted vegetation index, version two (MSAVI2) and normalized difference water index (NDWI) spectral indices were obtained and analyzed, comparing the responses of two covered vineyards with different plastic sheets in respect of two uncovered ones. Results demonstrated that no significant limitation (for both bands and spectral indices) was introduced by plastic sheets while monitoring spectral behavior of covered vineyards.

An approximation algorithm for submodular hitting set problem with linear penalties

The hitting set problem is a generalization of the vertex cover problem to hypergraphs. Xu et al. (Theor Comput Sci 630:117–125, 2016) presented a primal-dual algorithm for the submodular vertex cover problem with linear/submodular penalties. Motivated by their work, we study the submodular hitting set problem with linear penalties (SHSLP). The goal of the SHSLP is to select a vertex subset in the hypergraph to cover some hyperedges and penalize the uncovered ones such that the total cost of covering and penalty is minimized. Based on the primal-dual scheme, we obtain a k-approximation algorithm for the SHSLP, where k is the maximum number of vertices in all hyperedges.

Effect of Conductive Layer Condition on the Morphology of Anodic Aluminum Oxide Template-Assisted Indium Antimonide Nanowires.

Indium antimonide nanowires were synthesized by electrochemical deposition using anodic aluminum oxide template in the presence of gold film as conductive layers. Field emission scanning electron microscopy and energy dispersive X-ray spectrometry measurements were carried out to investigate the effect of adhesive insulated tape covered below the conductive layer. Results showed that the anodic aluminum oxide template covered with insulating tapes had better morphology with less presence of overgrown rough film on the topside of the anodic aluminum oxide template and it exhibited a smoother nanowire sidewall as compared to the uncovered ones. Additionally, the unique properties of anodic aluminum oxide were controllable pore diameter with a narrow size distribution at some intervals. It was evident from the energy dispersive X-ray spectrum that the nanowires synthesized from the covered template condition exhibited better InSb composition and stoichiometric ratio compared to the uncovered template condition.

Effects of a photoselective netting system on Fuji and Jonagold apples in a Mediterranean orchard

An assessment of a red photoselective netting system on apple production was conducted in a Mediterranean semi-arid climate. For two seasons, blocks of trees from an early bearing (cv Jonagold) and late bearing (cv Fuji) cultivars were covered to full canopy with red photoselective nets with 20% shading factor and an exclusion mesh size of 5.2 × 2.1 mm in an experimental orchard and compared to uncovered blocks of trees in the same orchard. The influence of nets on microclimate was assessed by measuring light intensity, Photosynthetic active radiation (PAR), Air temperature and relative humidity. An average decrease of 22.8% in light intensity along with a reduction in the average PAR radiation incidence by 23% improved the leaves photosynthesis efficiency with no influence on air temperature and relative humidity. The nets, installed after petal fall, had no significant influence on annual shoot growth and fruit set.At harvest, apples taken from netted trees were better graded than in the control in terms of both quality and quantity. Fruit weight, size and color blush were significantly higher in apples grown under nets compared to uncovered ones in both cultivars. While apple firmness was slightly lower under nets, no significant differences were reported in terms of sugar content and malic acid between both treatments.Nets significantly reduced the population of codling moth and the fruit damages caused by this pest without use of insecticides. Nets also decreased the amount of fruit fly caught in traps. No differences were recorded in terms of powdery mildew occurrence, aphids, mites and leafminer populations between both treatments. At last, nets also protected apples from sunburn and bird damages.To our knowledge, this is the first overall assessment of apple production in a pest-exclusion setting using red photoselective nets.

Experimental evaluation of self-expandable metallic tracheobronchial stents

Abstract The self-expandable metallic stents have been widely used in tracheobronchial obstruction or fistulation, including the J-shaped and Y-shaped stents, named after the shape of the branch-stem junction of the stent. However, there is scarce data on the mechanical performance of these tracheobronchial stents, which is essential for optimal stent implantation. In this work, eight self-expandable metallic tracheobronchial stents in three types (i.e., straight, J-shaped, and Y-shaped), with or without cover, were characterized. The compression resistance of the stems was investigated through both compression and indentation tests. The bending resistance of the branches in the J-shaped and Y-shaped stents was assessed through the bending test. Our results demonstrated that the covered stents exhibited a significantly higher compression resistance and bending resistance than the uncovered ones. The branches had a minimal impact on the compression resistance of the stem. The branch of the J-shaped stent showed a significantly lower bending resistance than the Y shaped one. This work provides a testing framework for the J-shaped and Y-shaped stents,which could shed some light on the optimal design of stent with branches.

Field assessment in single-housed cats of litter box type (covered/uncovered) preferences for defecation

Cats living without any outdoor access have to use litter boxes to eliminate. A lack of cleanliness is one of the main reasons for which cat owners consult their veterinarian. What has been identified as one of the major causes for this problem is an inappropriate spot for elimination which does not fit the cats' needs. The following measures are generally agreed about litter boxes: easily accessible in a quiet spot, appropriate size, sufficient number for the size of the home, and the number of cats. The choice of the litter box is mainly influenced by cat owners themselves as much as by commercial availability, rather than by scientific recommendation. The purpose of the present study was to assess which litter box type would be chosen by single-housed cats: a covered (closed) or an uncovered (open) litter box. A field test has been set up to analyze the cats' preferences, and two 4-week studies were conducted. During the first study, which included 13 cats, both litter boxes had the same surface area, whereas in the second study, which included 12 cats, the covered litter boxes had a surface area which was 17% larger than the uncovered ones. The cat's preference was assessed by daily counting of the feces in the boxes. When the surface area was the same, a tendency was in favor of the covered litter boxes with a significant difference at 10% threshold (P = 0.085) but not at a 5% threshold. This difference becomes significant at a 5% threshold (P = 0.011) in the second study in which the 17% difference in surface area clearly favored the covered litter boxes. Cats may prefer commercially available covered litter boxes as opposed to uncovered ones, if they have a larger surface area.

Cracking and quality attributes of jujube fruits as affected by covering and pre-harvest Parka and GA3 treatments

Abstract This study was carried out to investigate the effects of rain protective covering (RPC) together with Parka and gibberellic acid (GA3) treatments on cracking rates and quality attributes of jujube fruits. RPC was mounted 5 weeks before the commercial harvest date. 1% Parka (containing 7.5% stearic acid, 5% cellulose and 1% calcium) and GA3 (15 mg L−1) were sprayed to experimental trees 3 and 2 weeks before the commercial harvest date. As compared to the control, all treatments (Parka, GA3 and GA3+Parka) yielded lower cracking rates. Cracking rates were also significantly lower in covered trees than in uncovered trees. However, GA3+Parka treated fruit had significantly lower cracking rates than both the control and the other treatments. GA3 treated fruits had significantly higher weight, width, hue angle and firmness values, but significantly lower L* values than the control fruits. As compared to the control, all treatments yielded a significantly lower respiration rate and soluble solids content, but higher titratable acidity, vitamin C and total phenolics. The covered fruits had significantly higher hue angle, respiration rate, vitamin C, total phenolics, total flavonoids and antioxidant activity (free radical scavenging activity on DPPH and FRAP) than the uncovered ones. It was concluded based on the present findings that rain-protective covering could be used as an efficient tool to reduce cracking rates in jujube fruits without any negative effects on the other quality attributes. It was also concluded that Parka and GA3 treatments reduced cracking rates significantly and such a reduction was more remarkable with combined GA3+Parka treatments.

Fibroblast and pre-osteoblast cell adhesive behavior on titanium alloy coated with diamond film

It is well known that titanium alloys have mechanical strengths comparable to steels, as well as high corrosion resistance. Also, they have the advantage of promoting osseointegration, when used in medical and dental implants. This work aims to describe the adhesion properties of fibroblast and osteoblast cells on the surface of titanium aluminum vanadium alloy (Ti6Al4V). Three different conditions of the surface were investigated: smooth, rough and covered with diamond film. Conventional material characterizations were performed to the film which consisted in: Morphological visualization by scanning electron microscopy, confocal profilometry, X-ray diffraction pattern, Raman backscattering spectroscopy and atomic force microscopy. Biocompatibility tests of Ti6Al4V were performed using primary human fibroblasts and mouse pre-osteoblasts cell line MC3T3-E1. Overall, diamond films deposited on Ti6Al4V showed interesting results of uniformity and protection against cracks on to the surface, reasonable biocompatibility features if compared to uncovered ones, indicating that this film is an alternative for using in health care applications.

Importance of ion bombardment during coverage of Au nanoparticles on their structural features and optical response

This work studies the changes in the optical response and morphological features of 6 ± 1 nm diameter Au nanoparticles (NPs) when covered by a layer of a-Al2O3 by pulsed laser deposition (PLD). The laser fluence used for ablating the Al2O3 target is varied in order to modify the kinetic energy (KE) of the species bombarding the NPs during their coverage. When the ion KE < 200 eV, the structural features and optical properties of the NPs are close to those of uncovered ones. Otherwise, a shift to the blue and a strong damping of the surface plasmon resonance is observed as fluence is increased. There are two processes responsible for these changes, both related to aluminum ions arriving to the substrate during the coverage process, i.e., sputtering of the metal and implantation of aluminum species in the metal. Both processes have been simulated using standard models for ion bombardment, the calculated effective implanted depths allow explaining the observed changes in the optical response, and the use of a size-dependent sputtering coefficient for the Au NPs predicts the experimental sputtering fractions. In spite of the work is based on PLD, the concepts investigated and conclusions can straightforwardly be extrapolated to other physical vapor deposition techniques or processes involving ion bombardment of metal NPs by ions having KE > 200 eV.

Wideband radiation enhancement of waveguide arrays operated as feeds for reflector antennas using patch array covers

[1] This work rigorously analyzes a periodic microstrip patch array printed on a dielectric slab and placed over an array of open-ended sidewall loaded rectangular waveguides. The method of moments using spectral Green's functions for multilayer structures is employed. The application selected to feature the computed results of this structure is array matching. This work thus investigates the ability of such patch arrays to improve the transmission levels of waveguide arrays over those of uncovered ones. The matching performance is also compared with conventional dielectric sheath-type tuners. Two array operation scenarios are studied: direct radiating phased arrays, and focal plane arrays as feeds for reflectors. Earlier studies of the latter scenario show that the decoupling efficiency tends to be poor at low frequencies, due to the electrical proximity between the waveguide elements. It will be demonstrated here that both forms of matching layers can be tuned to provide good matching at low frequencies. This study has opted to investigate the beneficial effects of the sheet and the patch array over a wide frequency band, rather than its optimization over a selected narrow band. Such optimizations can be done in practice for known specific operating bands.

Disponibilidade hídrica, radiação solar e fotossíntese em videiras 'Cabernet Sauvignon' sob cultivo protegido

O objetivo deste trabalho foi avaliar os efeitos da cobertura de videira 'Cabernet Sauvignon' com lona plástica translúcida sobre a disponibilidade de luz e água, a concentração foliar de clorofila e a fotossíntese. As plantas com cinco anos de idade foram conduzidas em sistema 'Y' sobre porta-enxerto Paulsen 1103. O experimento seguiu o delineamento em blocos ao acaso, com dois tratamentos (plantas sem e com cobertura plástica) e quatro repetições de 15 plantas (unidade experimental). A cobertura plástica reduziu o suprimento às plantas de radiações ultravioleta (UV), azul, verde, vermelho, vermelho distante e total (300-750 nm), bem como a disponibilidade hídrica nas camadas superficiais do solo (0-30 cm). As plantas cobertas apresentaram maior taxa fotossintética máxima e condutância estomática em relação às plantas descobertas. Os pontos de compensação e de saturação de luz, a eficiência quântica aparente, a respiração no escuro, a concentração foliar de clorofilas e o potencial hídrico foliar de base não foram influenciados pelo uso da cobertura plástica. A cobertura plástica reduziu a radiação e a disponibilidade hídrica nas camadas superficiais do solo, porém favoreceu a assimilação foliar de CO2.

Feasibility and safety of placement of a newly designed, fully covered self-expandable metal stent for refractory benign pancreatic ductal strictures: a pilot study (with video)

Painful chronic pancreatitis with main pancreatic ductal strictures is usually managed with endotherapy with a plastic stent. To date, the role of placement of metallic stents, especially uncovered ones in benign pancreatic ductal stricture, has been unsatisfactory as a result of stent dysfunction related to mucosal hyperplasia. We explored the feasibility and safety of temporary placement of a newly designed, fully covered self-expandable metal stent (FCSEMS) in painful chronic pancreatitis and refractory benign pancreatic ductal strictures. A prospective pilot and feasibility study. A tertiary academic center. Thirteen patients with chronic painful pancreatitis of alcoholic (8) or idiopathic (5) etiology. ERCP with temporary FCSEMS placement (2 months). Endoscopic removal of FCSEMSs was performed with a snare or rat-tooth forceps. End points were feasibility, safety, and morbidity. Successful FCSEMS placement was performed in all enrolled patients. After immediate placement of FCSEMS, 2 patients had mild acute pancreatitis related mainly to the stricture dilation procedure (Soehendra stent retriever or balloon dilation). Complications associated with stent placement included 5 migrations (39%, 1 proximal and 4 distal) and 2 incidents of cholestatic liver dysfunction associated with the compression of the bile duct orifice by expansion of FCSEMSs. In 1 patient with proximal migration, the stent was repositioned by an inflated retrieval balloon. Additional endoscopic biliary sphincterotomy with or without biliary stenting was performed in 2 patients with cholestatic liver dysfunction. There was no occurrence of pancreatic sepsis among any patients. FCSEMSs were removed from 9 of 9 patients without stent migration (100% [9/9] as per protocol, and 69% [9/13] as intention to treat, respectively). Improvement or resolution of the pancreatic ductal strictures was confirmed in all 13 patients on follow-up ERCP (2 months after stent placement), regardless of stent migration. Small patient populations without long-term follow-up. Two-month placement of FCSEMSs in patients with refractory benign pancreatic ductal strictures may be feasible and relatively safe. However, stent migration was not uncommon. A further investigation with ideal stent design may therefore be needed before recommending FCSEMSs as a therapeutic option for refractory benign pancreatic ductal strictures.

Polinização em flores de abacateiro (Persea americana Mill.)

The experiment aimed to study the frequency, nectar and/or pollen and hoarding time of bees in avocado flowers and verify the effect of their visits on fruit production. Six inflorescences (three covered and three uncovered) with two replications were marked to evaluate the effect of cross pollination on fruition percentage. The honey bees showed two peaks of hoarding (by 11 to 12 a.m. and 5 p.m.) following the flowers opening of different avocado groups (groups A and B), as much for nectar as for pollen. However, the honey bees presented a longer peak in the morning than in the afternoon for nectar, in 1997, and changed in 1998. There was no difference between the periods, for pollen. The fruition percentage was significantly different between the covered treatments (produced less) and uncovered ones (produced more). The crop reduced 81.25% without pollinators

Comportamento vegetativo e produtivo de videiras 'Cabernet sauvignon' cultivadas sob cobertura plástica

O uso de cobertura plástica no cultivo de videira encontra-se em expansão no Rio Grande do Sul, por ser uma alternativa que visa a proteger as plantas da precipitação pluvial e do granizo. O objetivo deste estudo foi avaliar os impactos de uma cobertura plástica translúcida e impermeável sobre a fenologia, o crescimento (de ramos, folhas, cachos e bagas) e a produtividade em videiras 'Cabernet Sauvignon' (Vitis vinifera L.), com cinco anos de idade, conduzidas em sistema 'Y', sobre porta-enxerto Paulsen 1103. O experimento, conduzido no município de Caxias do Sul-RS, seguiu o delineamento em blocos ao acaso, tendo os tratamentos sem e com cobertura plástica, com quatro repetições de 15 plantas (unidade experimental). As alterações microclimáticas impostas pela cobertura plástica não foram expressivas para alterar a fenologia da videira. As plantas cultivadas sob cobertura plástica apresentaram maiores valores de comprimento e massa fresca de ramos e de área, e massa seca foliar em comparação às plantas descobertas. O peso e o diâmetro de bagas foram superiores nas videiras cobertas apenas no início do ciclo e não diferiram próximo da colheita. As demais variáveis analisadas não foram afetadas pela cobertura plástica. A cobertura plástica interferiu no crescimento vegetativo das plantas, mas não afetou a produção.

Endoscopic removal of malfunctioning biliary self-expandable metallic stents

Endoscopic removal of malfunctioning self-expandable metallic biliary stents (SEMS) is difficult and not well described. The aim of this study is to review the indications, the techniques, and the results of SEMS removal in a cohort of patients with malfunctioning stents. All patients who underwent an attempt at endoscopic removal of biliary SEMS over a 5-year period were retrospectively identified. The main indications for SEMS removal were the following: distal migration of the stent or impaction to the duodenum, impaction into the bile-duct wall, tissue ingrowth, and inappropriate length of the stent causing occlusion of intrahepatic ducts. SEMS were removed by using foreign-body forceps or polypectomy snares. Endoscopic removal of 39 SEMS (13 uncovered and 26 covered) was attempted in 29 patients (17 men; mean age, 66 years). SEMS extraction was attempted after a mean of 7.5 months (8.75 months standard deviation) post-SEMS insertion. Removal was successful in 20 patients (68.9%) and in 29 SEMS (74.3%). Covered SEMS were effectively removed more frequently than uncovered ones: 24 of 26 (92.3%) and 5 of 13 (38.4%), respectively (p < 0.05). No major complications were recorded. Multivariate analysis showed that the time interval between insertion and removal, SEMS length, stent-mesh design (zigzag vs. interlaced), and indication for removal were not predictive of success at stent removal. Endoscopic removal of biliary SEMS is feasible and safe in more than 70% of cases. Because only 38% of uncovered SEMS were removable, the presence of a stent covering is the only factor predictive of successful stent extraction. The presence of diffuse and severe ingrowth was the main feature limiting SEMS removal.

A-SiC:H films as perspective wear-resistant coatings

Amorphous hydrogenated silicon carbide (a-SiC:H) films have been deposited from methyltrichlorosilane (MTCS) in a 40.56 MHz PECVD reactor with an additional bias at a substrate. The substrates were crystalline silicon wafers. The as-deposited films consist of approximately 60–70 at.% Si, 20–30 at.% C, up to 8 at.% O and 0.8% Cl. The thickness of the coatings was approximately 0.2–0.4 μm. Film morphology investigations have shown that the coatings are homogeneous, and the substrate-coating zone points to the high adhesion of the coating to the substrate. From nanoindentation tests it follows that a-SiC:H coatings demonstrate the hardness up to 10 GPa and elastic modulus of 118 GPa. The samples annealed at 600 °C have higher hardness than the as-deposited films (by approx. 25%). Ball-on-plane tests have revealed that the abrasive wear resistance of the covered substrates is 1.5–4 times higher than that of the un-covered ones. So, despite the comparatively low hardness, the a-SiC:H films demonstrate good tribological properties, which make them suitable for applying as low-cost wear-resistant coatings. The possible mechanisms describing the tribological properties of a-SiC:H films are discussed.

A-SiC:H films as perspective wear-resistant coatings

Amorphous hydrogenated silicon carbide (a-SiC:H) films have been deposited from methyltrichlorosilane (MTCS) in a 40.56 MHz PECVD reactor with an additional bias at a substrate. The substrates were crystalline silicon wafers. The as-deposited films consist of approximately 60–70 at.% Si, 20–30 at.% C, up to 8 at.% O and 0.8% Cl. The thickness of the coatings was approximately 0.2–0.4 μm. Film morphology investigations have shown that the coatings are homogeneous, and the substrate-coating zone points to the high adhesion of the coating to the substrate. From nanoindentation tests it follows that a-SiC:H coatings demonstrate the hardness up to 10 GPa and elastic modulus of 118 GPa. The samples annealed at 600 °C have higher hardness than the as-deposited films (by approx. 25%). Ball-on-plane tests have revealed that the abrasive wear resistance of the covered substrates is 1.5–4 times higher than that of the un-covered ones. So, despite the comparatively low hardness, the a-SiC:H films demonstrate good tribological properties, which make them suitable for applying as low-cost wear-resistant coatings. The possible mechanisms describing the tribological properties of a-SiC:H films are discussed.