Loose Fibers Research Articles

The influence of forming surface on the vacuum pressure in hydroentangling process

Hydroentangling is a process that uses waterjet curtains issued from a series of parallel jet-heads (manifolds) for entangling and interloping fibres in a loose fibre web carried on a belt or perforated surface. The efficient removal of the stagnant water remaining from each waterjet curtain is crucial for the success of fibre entanglement when the web reaches the next jet-head. In this article, we discuss different methodologies that can be used to calculate the minimum vacuum pressure required for extracting the hydroentangling water from non-woven fabrics. A distinction has been made between hydroentangling on tightly and openly woven screens and different modelling strategies are recommended for each. In particular, it is demonstrated that a one-dimensional flow pattern coupled with available analytical permeability expressions can be used to predict the required vacuum pressure in the case of tightly woven screens. In the case of open woven screens where the flow pattern becomes three-dimensional, numerical simulation is needed for calculating the vacuum pressure required for complete removal of hydroentangling water. We also demonstrated that the vacuum pressure increases by decreasing the fibre diameter or increasing the fabrics' solid volume fractions.

Histopathological comparison between endofibrosis of the high-performance cyclist and atherosclerosis in the external iliac artery

High performance athletes, predominantly professional cyclists, can develop symptomatic arterial flow restriction in one or both legs during exercise. The ischemic symptoms are caused by endofibrosis and/or kinking of the external iliac artery. Because these athletes are young and have no classic risk factors for atherosclerosis, endofibrosis and atherosclerosis are considered different disease entities. We compared histology of endofibrotic lesions from young sportsmen with atherosclerotic lesions of the external iliac artery in elderly individuals. Nineteen external iliac endarterectomy specimens from 18 cyclists (age 29 +/- 8 years) were compared with 42 external iliac segments from 22 elderly individuals (82 +/- 10 years). Ten arteries from elderly individuals revealed an intimal area that was >or=25% of the area encompassed by the internal elastic lamina and were considered atherosclerotic lesions. Stenosis was higher in patients (65% [interquartile range 50-75]) than in controls (11% [7-24]) (P < .0001). The endofibrotic lesions revealed loose connective tissue with moderate to high cellularity. Both in endofibrosis and atherosclerosis, most cells in the lesion were smooth muscle actin positive. In the endofibrosis specimens, loose fibers of collagen were observed, whereas in the atherosclerotic lesions collagen was mostly densely packed. Calcification of the lesion was not observed in endofibrotic lesions, whereas calcium deposition was observed in 80% of atherosclerotic lesions. Lymphocytes were present in 21% of endofibrotic lesions and in 80% of atherosclerotic cases. Macrophages were observed in 16% of endofibrotic lesions and in all atherosclerotic plaques. Luminal thrombosis was observed in one case of endofibrosis. In the external iliac artery, atherosclerotic lesions and endofibrotic lesions of high performance cyclists have distinct morphologic characteristics. Endofibrosis in the external iliac artery may serve as soil for luminal thrombosis.

Blending of Natural Fibres and Thermoplastics by Screwless Extrusion

Natural fibres, such as sisal, flax and woodfibres, are relatively inexpensive and originate from renewable resources. Thermoplastic polymers, such as polypropylene (PP), high density polyethylene (HDPE) and waste plastics, possess shorter manufacturing cycle times and reprocessability. Natural fibre-reinforced thermoplastic composite materials exhibit favourable values of modulus and strength when the fibres are properly compounded with the polymers. Common methods for manufacturing natural fibre-reinforced thermoplastic composites, injection moulding and extrusion, require pre-compounding of the fibres and the thermoplastic due to the large difference in densities of the loose fibres and thermoplastic materials. Development and analysis of a screwless extruder that employs a reliable and low technology process for melt blending natural fibres and thermoplastic polymers is the main objective of this study.

An Unusual Cause of Cardioembolic Stroke

Isolated left ventricular noncompaction (ILVNC) is a rare congenital condition that is the result of an intrauterine developmental arrest, which stops the compaction of the loose myocardial fiber meshwork of the left ventricle. This condition is recognized by an excessively prominent trabecular meshwork and deep intertrabecular recesses of the left ventricle. Although these intertrabecular recesses are prone to thrombus formation, with resulting embolic sequelae, the literature describes only 1 adult case of a stroke caused by ILVNC. We describe a case of cerebral cardioembolism in a 33-year-old man due to ILVNC. Because of echocardiography (ECHO) findings in this case, cardiac magnetic resonance imaging (cMRI) was performed, which allowed a definite diagnosis to be obtained. This case should highlight the importance of performing cMRI especially in younger patients with embolic stroke, if the ECHO suggests a suspected myocardial disorder.

Vascular Arrangement and Ultrastructure of the European Eelpout Zoarces viviparus Ovary: Implications for Maternal–Embryonic Exchange

The structural basis for exchange between maternal serum and ovarian fluid in the viviparous teleost Zoarces viviparus was investigated. Casts of the ovarian vasculature showed that blood supply to the ovary is initially directed to the follicular appendages lining the ovarian wall through thick-walled muscular arteries running along the ovary wall and within the follicular appendages. The follicles had a rich capillary network with diffusion distances between maternal blood and ovarian fluid comparable to those found for gill epithelia, suggesting this is the primary site of gas exchange between maternal plasma and ovarian fluid. Follicular capillary beds were continuous with those in the ovary wall and were eventually drained by the ovarian and intestinal venous systems. The barrier between ovarian fluid and maternal blood consisted of the endothelial cells of the maternal blood vessels and a layer of epithelial cells lining the ovarian lumen, with an intermittent layer of loose connective fibers. Junctional complexes between cells were predominantly anchoring junctions with the occurrence of occasional occluding junctions, supporting the possibility of paracellular transport from maternal serum to ovarian fluid of small molecular weight compounds. Heavy investment in keratin filaments suggests that follicles are tissues of high structural integrity. Evidence for protein synthesis in the ovarian lining was found in the form of Golgi apparatus and rough endoplasmic reticulum. Although numerous cytoplasmic vacuoles and secretory granules were present in both epithelial and endothelial cells, the fate of synthesized protein remains to be determined.

Further Characterization of the Muscle Layers and Lamina Propria of the Urinary Bladder by Systematic Histologic Mapping

The muscularis mucosae (MM) and muscularis propria (MP) are important landmarks for pathologic tumor (pT) staging of urinary bladder cancer, which is the quintessential prognostic factor. In our routine practice, we have occasionally noted patterns of MM, which do not always conform to the originally described configuration of thin slender bundles arranged in a single layer of interrupted, dispersed, or continuous muscle. We evaluated the lamina propria (LP), MM, and MP characteristics in 35 urinary bladder resection specimens with systematic sampling from the dome, trigone, anterior, posterior, right, and left lateral walls. Among the subsites, the trigone had a relatively flatter surface and attenuated LP depth (0.46 to 1.58 mm), about half of the thickest region which was the dome (0.98 to 3.07 mm). The MM was typically in individual or small groups of slender and wavy fascicles or wispy fibers. MM also had focal to rarely extensive hyperplastic appearance (53%, most common in dome) with 2 recognizable patterns: (a) aggregates of hyperplastic MM with haphazard outlines (33%) distinct from that of MP, and (b) hyperplastic compact MM with parallel muscle fibers and regular outline arranged singly or in small groups (45%) that occasionally strongly resembled MP muscle but distinguishable from it on the basis of the location in the LP. By distribution, these muscle bundles were more typically dispersed or formed a discernable layer (41%) as discontinuous or infrequently near-continuous layer. The LP vascular plexus was present in every section most often in association with the MM muscle; however, variations in the distribution were observed. The MP most commonly had a relatively regular interface with the LP. A distinctive pattern was noted in the trigone where occasionally there was gradual diminution of size of the MP muscle bundles as they extended to almost a suburothelial location. In 22%, isolated or small groups of compact regular hyperplastic MM muscle bundles were noted in deep LP situated between the more typical slender MM layer and the MP. In conclusion, there are additional patterns of MM other than previously described. Awareness of the occasionally hyperplastic appearance of MM muscle is important to prevent overstaging of invasive urothelial carcinoma. In transurethral resection specimens, lack of orientation may preclude distinction of the hyperplastic MM from true MP in these rare situations. The number and orientation of muscle bundles, relationship to urothelium and vascular plexus, and comparison with more characteristic MP, if present, would be helpful; isolated bundles immediately adjacent to the urothelium with loose haphazard fiber orientation and irregular outlines favor MM over MP muscle. The hyperplastic MM mimicking MP may be more challenging; isolated muscle bundles immediately adjacent to the urothelium would favor hyperplastic pattern of MM over MP muscle. Topographical variations exist among the subsites, the more superficial location of the MP and the rarity of MM in the trigone, relative abundance of hyperplastic MM in dome, and presence of the more superficial ureteral MP at its insertion in the bladder complicate the traditional pT stage evaluation of invasion in these regions. The inconsistency of a distinct MM layer and variations in the LP vascular plexus indicate that substaging of pT1 would be problematic and thus provides further support to the World Health Organization/International Society of Urological Pathology 1998 and World Health Organization 2004 recommendation against its implementation at the current time.

The relationship between performance of submerged hollow fibers and bubble-induced phenomena examined by particle image velocimetry

Aeration is used in many membrane processes, especially in submerged membrane bio-reactors (MBRs). In order to reduce the costs of operation, it is important to optimize the bubble size and frequency. For a given airflow rate, it is possible to have many small bubbles at a high frequency, or a few larger bubbles at a lower frequency. The objective of this study was to determine the effects of bubbling flow on the performance of tight and loose submerged fibers. Parameters varied included the bubble size, bubble frequency, degree of looseness and the channel width. Particle image velocimetry was used to observe liquid flow patterns and measure the surface shear stresses as well as characterize the movement of the hollow fibers. Filtration behavior was examined for a model bentonite suspension at constant flux by monitoring transmembrane pressure (TMP) rise. For tight fibers, it was found that similar rates of increase of TMP can be achieved by using up to 10 times less air if small bubbles are used at a higher frequency. The reason for this was that although smaller bubbles produced a lower average shear stress, the fluctuations in the shear stress (characterized by the standard deviation) was a key factor in improving performance. The performance of the fiber was enhanced when a degree of looseness was allowed. For loose fibers, it was also found that using smaller bubbles at high frequency could provide the same performance at lower airflow rates. There was an optimum looseness for a single fiber when bubbling was applied. The bubble-induced phenomena that controlled performance for loose fibers appeared to be a combination of fiber acceleration and the standard deviation of the shear stress.

Effect of Nozzle Geometry on the Flow Dynamics of Hydroentangling Jet

Hydroentangling technique uses extremely fine nozzles to direct high-energy water jets against a loose fiber web. This study investigates the effect of nozzle geometry on the flow dynamics of hydroentangling jet by simulating water-jet formation from cone-up, streamline, and cone-down geometries. The simulation results reveal that water contacts with the nozzle wall all the way when it goes through the cone-up and streamline nozzles. In contrast, the cone-down geometry can form a constricted water-jet because of a sharp turning angle at the nozzle entrance. Consequently, the cone-down nozzle has higher velocity coefficient and the water-jet discharged from the nozzle has a longer intact length than the two others because of the absence of cavitation and wall friction. Part of the results is in excellent agreement with earlier experimental studies.

Analysis of Brillouin Scattering Based Fiber Optic Sensor Bonding Effects

Brillouin scattering based sensors can measure strain and/or temperature at all points along an optical fiber; first, the fiber must be calibrated. A problem arises because the temperature coefficient of a fiber bonded to a host is changed by the host structure. Using the loose fiber coefficient could lead to large strain and temperature measurement errors. This article studies the change in the Brillouin temperature coefficient due to bonding. The intrinsic Brillouin temperature coefficient of two fibers is also found. This coefficient allows accurate strain and temperature measurements to be made, assuming the coefficient of thermal expansion of the host is known.

Giant skin tags: Report of two cases

Skin tags are skin-colored, pedunculated tumors with a smooth surface. Histologically are composed by loose collagen fibers and dilated capillaries. Giant skin tags are reported rarely in the literature. We present the case of two giant skin tags on labium majus. To our knowledge, these are the largest skin tags reported.

Ultrastructure of Bone Cells in Paget's Disease of Bone

Ultrastructure of Bone Cells in Paget's Disease of Bone

Changes in the Functional Structure of the Tenosynovium in Idiopathic Carpal Tunnel Syndrome: A Scanning Electron Microscope Study

The subsynovial connective tissue lies between the flexor tendons and visceral synovium in the carpal tunnel. Although tenosynovial fibrosis is nearly universally noted in patients with carpal tunnel syndrome, the relationship, if any, between the fibrosis and nerve abnormalities is unknown. The authors used light and scanning electron microscope imaging of the subsynovial connective tissue to gather information about its organization. Human subsynovial connective tissue was studied to determine its ultrastructural morphology. Biopsy specimens of 11 patients (12 hands) with idiopathic carpal tunnel syndrome, 14 cadaver controls, and two cadavers with a history of carpal tunnel syndrome were obtained for scanning electron microscopic imaging and histopathologic examination. The visceral synovial layer is an uninterrupted membrane that defines the bursa dorsally. The subsynovial connective tissue consists of fibrous bundles that run parallel to the tendon, interconnected by smaller fibrous fibers. It connects to the synovial membrane and the flexor tendons. During tendon motion, the loose fibers between adjacent layers are stretched. The control tissue showed interconnections between all the parallel layers, whereas in patients with idiopathic carpal tunnel syndrome, these interconnections were absent, replaced with thicker parallel fibrous bundles. Similar changes were found in the cadaver carpal tunnel syndrome specimens. Pathologic changes in the patient and cadaver carpal tunnel syndrome specimens were most apparent close to the tendon and became progressively less severe in more superficial layers. The authors' observation that the most severe changes in the subsynovial connective tissue were found close to the tendon suggests that these changes may be the result of a shearing injury.

Study on a rat model of filtering bleb scarring formation

To investigate a rat animal model of filtering bleb scarring formation. Thirty-five of Sprague-Dawley (SD) rats were used in this experiment. The filtration surgery was performed on one eye of each rat and the other eye served as control. The presence of postoperative bleb and clinical manifestation was evaluated. Each group of three rats were sacrificed and the eyes enucleated on day 1, 3, 7, 14, and 28. After the eyes were fixed by 10% formalin, serial paraffin sections of three eyes were labeled with HE staining and the pathological morphology was observed under a microscope. A conjunctival bleb was successfully formed in 35 rats lasting from 8 to 21 days after surgery. An obvious dilatation of blood vessels, infiltration of a great number of neutrophil, and a severe edema of the subconjunctival tissue were observed on day 1 and the above morphological changes plus increased infiltration of macrophages were found on day 3. The dilated blood vessels were lessened while the proliferation of fibroblast was presented with abundant endochylema in oval-shaped nucleus of fibroblasts, which were closely associated with the deposition of small amount of new loose collagen fibers on day 7. The collagen fibers became tight on day 14 and subsequently, the early scar was formed on day 28. The rat model of filtering bleb scarring formation may be useful for the investigation of preventing and treating conjunctival scarring resulted from glaucoma filtration surgery and other related eye diseases in the future.

Efficiency of oil removal from real wastewater with different sorbent materials

The aim of this paper was to investigate the efficiency of different sorbent materials for oil removal from wastewater. Two types of sorbents were investigated: organic (loose natural wool fibers (NWF) and recycled wool based nonwoven material (RWNM)) and inorganic (sepiolite). Sorption was carried out in continuous tubular contractor (initial oil concentration of 1511 mg/dm 3) and batch tank (initial oil concentration of 5066 mg/dm 3). Wool-based sorbents showed higher sorption capacity (5.56 g/g for NWF and 5.48 g/g for RWNM) compared to sepiolite (0.19 g/g) in case of sorption in batch tank. The study on sorption in continuous tubular contractor suggested that volume of oily wastewater strongly affected oil removal. The results indicated that the combination of extractive-gravimetric and FTIR spectrophotometric methods can be recommended for precise determination of oil concentration, being suitable as a controlling tool for oil detection.

한국산 퉁가리과 (Amblycipitidge) 어류 2종 수염의 조직 학적 구조

Histological observations of the barbels of torrent catfish (Amblycipitidae) in Korea are reported. The bullhead torrent catfish (Liobagrus andersoni) and Korean torrent catfish (L. obesus) have eight obvious barbels in two pairs each on the maxilla and mandible. Each barbel is composed of an epidermis, dermis, and central cartilagerod. The epidermis of the maxillary and mandibular barbels of the bullhead torrent catfish is thicker than that of the Korean torrent catfish (P<0.05) and is formed of stratified epithelium that contains many cutaneous taste buds and a few small club cells. There are many taste buds on the upper part of each barbel. The dermis consists of loose connective tissue fibers that enclose blood vessels and bundles of nerve fibers. The barbels of these fish can be categorized into stiff and flexible types and are accessory, feeding, and sensory structures. Our results validate the barbels as gustatory receptor organs for these fishes.

Hydroentangling knitted fabrics for improving abrasion resistance

Hydroentangling is used as the mechanical finish to improve abrasion resistance of knitted fabrics. The hydroentangling process successfully reduced the amount of loose surface fibers and led to improved abrasion resistance. However, other properties such as fabric thickness and softness were also affected by the treatment.

A study on flow through hydroentangling nozzles and their degradation

Hydroentangling is a technique for mechanically bonding loose filaments or fibers arranged in a web. The efficiency with which the web is entangled depends on the peculiar properties of laminar high-speed waterjets used. The characteristics of such waterjets strongly depend on the operating pressure and the nozzle inlet sharpness which influence the dynamics of fluid flow. In this study, we report on experiments and CFD simulations aimed at improving our knowledge of such two-phase flows. In particular, we simulate the formation and growth of the cavitation cloud inside a sharp-edge hydroentangling nozzle at pressures ranging from 10 to 200 bars ( 5700 < Re < 25 600 ) . Our experimental results run at the same pressures, confirm that nozzle cavitation will cause “hydraulic flip”. Once hydraulic flip occurs, atomizing waterjets will turn into constricted laminar waterjets with long intact lengths—a necessary condition for hydroentangling. It has been observed that the nozzle inlet deteriorates under high pressures. Our CFD simulations show a striking similarity between the contours of shear stress at the nozzle inlet and the nozzle wear pattern. These findings together with the SEM elemental analysis at the nozzle inlet reveal the potential for metal oxidation around the inlet, implicating stress-induced corrosion as a major contributor to the nozzle wear. Cavitation might also be one of the mechanisms responsible for the above-mentioned wear at the inlet edge. Additionally, our water-borne solid particle tracking, confirms SEM experimental results that particle deposition can potentially play a considerable role in the deterioration of the nozzle inlet shape.

Evaluation of interfacial relaxation due to water absorption in fiber–polymer composites

Water penetration in composite materials of different interfacial strengths has been studied and explained as the result of two parallel processes, i.e., diffusion through the polymer matrix and through a network of micro-channels formed along the imperfectly bonded polymer-fiber interface. Such channels along the exterior of the loose fiber are presumed to contribute a mesoscopic “free volume” to the composite which is conductive to diffusion. An analytical method based on an adaptation of the free volume theory approach is proposed for estimating the incipient looseness and any further interfacial relaxation caused by water absorption in composite materials.

Removing Interfering Contaminations from Gelatin Lifters

Gelatin lifter is widely used for recovering shoeprints from crime scenes. Dusty shoeprints removed from paper with loose fibers, cloth or plasterboard, might be concealed by the detached fibers. A novel technique to clean the gelatin lifter from the interfering contaminations, using adhesive lifters, was developed. The adhesive lifter is applied directly on the surface of the gelatin lifter, and is removed instantly. The adhesive lifter removes the upper layer of the attached material on the gelatin lifter. After removing the concealing material from the hidden imprint, the quality of the visualized imprint is improved. The cleaning process can be applied as many times as needed and the optimum number is different for each substrate. The small dust particles comprising the shoeprint remained attached to the sticky side of the gelatin lifter even though the adhesion force applied by the adhesive lifter is great. Repeating the procedure too many times could harm the quality of the print severely, yet the advantages of this method are greater than the risks of relocation of image quality reduction.

한국산 쓸종개, Plotosus lineatus (Thunberg) 수염의 조직

This paper deals with the histology of the barbels of striped sea catfish, Plotosus lineatus (Thunberg). This fish have eight noticeable barbels of two pairs on their maxillary and mandibular. Each barbel is composed of an epidermis, dermis and a central rod of cartilage. The epidermis in the middle part of the maxillary barbel is thicker than those on other parts, and formed of stratified epithelium which contains many cutaneous taste buds and a few small club cells. Number of taste buds increase on the middle and posterior part of each barbel. The dermis consists of loose connective tissue fibers which encloses blood vessels and bundles of nerve fibers. The barbels of this fish can be categorized into stiff and flexible types and are accessory, feeding and sensory structures. Thus we substantiate that they are gustatory receptor organs for this fish.