Length Of Worm Research Articles

Systematic Observation Of New Piscean Ptychobothriidaean Tapeworm From Mastacembelus Armatus At Marathwada Region (M.S.) India

Present study deals with Biosystematics of Piscean Ptychobothriidaean tapeworm Circumoncobothrium chavani Sp. Nov. collected from intestine of freshwater catfish host Mastacembelus armatus. (Lacepede, 1800) from different places of Marathwada Region (M.S.) India. The worm comes closer to all known species of the genus Circumoncobothrium (Shinde, 1968) in general topography of organ but differs due to having length of worm, scolex triangular, rostellum disc like, Mature segments broader than long, number and shape of testes, Ovary is bilobed.

Meshing theory of offsetting Archimedes cylindrical worm drive

The main purpose of this article is to establish the meshing theory for the offsetting Archimedes cylindrical worm drive, which consists of a cylindrical worm with asymmetric tooth profile and a plane worm gear. The equations of the tooth surfaces, the meshing function, the curvature interference limit function, and the curvature parameters are all obtained for the worm drive. By means of the developed reference-point-based meshing theory, the reference point located strictly on the tooth surfaces of a worm drive is determined via solving the system of nonlinear equations, in which no iteration is needed to perform this process. Based on the location of the reference point, the tooth surface boundaries are ascertained for the plane worm gear. The numerical case is carried out and the conjugate zone, the instantaneous contact lines, and the local meshing property parameters are acquired for the worm drive. The whole thread length of the cylindrical worm can almost be used and the conjugate zone can cover the whole tooth surface of the mating plane worm gear. In the meshing zone, not only the contact stress level between the tooth surfaces is relatively low, but also the lubrication condition is favorable. The comparative study on the meshing properties between the offsetting Archimedes cylindrical worm drive and the Archimedes conical worm drive is carried out.

Report of the Cestode Phyllobothrium chiloscyllii, Subhapradha, 1955 from Carcharhinus macloti

Present investigation deals with report of cestode Phyllobothrium chiloscyllii, Subhapradha, 1955 from Carcharhinus macloti at Alibag, Borali, Dighi, Shrivardhan, Murud,Raigad, West Coast of Maharashtra, India during the February, 2007 to January, 2009. The present tapeworm comes closer to Phyllobothrium chiloscyllii Subhapradha, 1955 with the characters such as length of worm, shape of bothridia, presence of long neck, arrangement of vagina and genital pore, but the same differs due to scolex (oval, China Rose shaped Vs. globular); Number of testes (30-40 Vs. 55-80); Ovary (transversely placed Vs. ‘U’ shaped) and Vitellaria (granular Vs. follicular). These are the minor characters hence it is redescribed here as Phyllobothrium chiloscylli Subhapradha, 1955.

Prevalence of Oxyuriasis and its Relationship With Eosinophilia in Children Aged 1 to 6 Years in Marand City, East Azerbaijan Province, Iran

Introduction: Enterobius vermicularis, commonly known as pinworm, is one of the most prevalent intestinal nematodes of humankind belonging to the Oxyuridae family. It is a small, white or transparent, threadlike roundworm. The length of the male worm is 2 to 3 mm and the female worm is 3 to 8 mm in length. This study was performed to determine the prevalence of E. vermicularis and its relationship with disease symptoms, allergic disease symptoms, and eosinophilia in children aged one to six years in Marand city of East Azerbaijan province, Iran. Methods: In this descriptive-analytical study, 200 children were studied using systematic random sampling. Data collection method was based on a questionnaire, peripheral blood smear, and Scotch tape test. In the designed questionnaire, children’s characteristics such as gender and age and parents’ characteristics including job and level of education were recorded. Peripheral blood smear slides were obtained from each child and examined for eosinophilia by a hematologist. Scotch test samples were prepared by parents after providing the necessary training on its sampling method and then examined in the laboratory for the presence of E. vermicularis eggs by a parasitologist. Results: In this study, 64 (32%) children were diagnosed with oxyuriasis. The prevalence of oxyuriasis was 36.5% in boys and 43.7% in girls. There was no significant relationship between oxyuriasis and its symptoms. Additionally, there was no significant relationship between oxyuriasis and allergic disease symptoms. Fourteen children had eosinophilia (7%), of which 9 (64%) were infected with E. vermicularis. There was a significant relationship between E. vermicularis infection and eosinophilia (P ˂ 0.05). Conclusion: According to the results of the study and the importance of the issue for the control and prevention of this disease, it is suggested that people should be provided with the necessary information about the life cycle, ways of transmission, and especially ways to prevent E. vermicularis infestation, and basic measures should be taken to improve the economic situation of the people of the region and to promote public and personal health through public education. Finally, medical treatment of patients and their families should be considered at the same time.

Morphologic and morphometric characteristics of ascaroid worm, Ophidascaris piscatori in Xenochrophis piscator snake in Sidoarjo, Indonesia.

Aim:The study was conducted to describe the morphology and morphometry of nematode worm in the stomach of Xenochrophis piscator snake macroscopically and microscopically using light and scanning electron microscopy (SEM).Materials and Methods:The sample was 40 nematode worms that have been collected from 60 snakes which slaughtered at snake slaughterhouses in Sidoarjo, Indonesia. The worms (10 male and 10 female) were stained with carmine, and the others were sent to Indonesian Science Institute for ultrastructure observation by SEM. Some of the female worms were immersed in physiological NaCl and incubated to collect the worm eggs.Results:Nematode worm in this study had three lips with almost the same size and it had papillae, so it was included in ascaridoid. The mouth of ascaridoids has three lips, the dorsal bearing two large outer papillae and the each lateroventral with one papilla. The body length and width of the male worm were 70-105 mm and 0.92-1.32, respectively, with head diameter of 0.22-0.28 mm. Dorsal and ventrolateral lips almost have the same size that was 0.10-0.12×0.11-0.13 mm. The length of interlabia was 0.06-0.08 mm, esophagus was 3.21-4 mm, tail was 0.17-0.23 mm, and spicule was 2.12-3.36 mm. The body length and width of the female worm were 85-130 mm and 1.28-1.71 mm, respectively. The head diameter was 0.29-0.38 mm. Dorsal and ventrolateral lips almost have the same size that was 0.13-0.16×0.15-0.19 mm. The interlabial length was 0.08-0.10 mm, esophagus was 3.04-4.67 mm, and tail was 0.22-0.31 mm. The distance of the vulva from the anterior edge was 56-88 mm with an average of 67.35 mm. The eggs have conspicuously pitted with length 0.08-0.09 mm and width 0.07-0.08 mm.Conclusion:Based on the characteristics of morphology and morphometry, the ascaroid worms found on X. piscator snake from Sidoarjo, Indonesia, were O. piscatori.

Study on the tolerance and adaptation of rats to Angiostrongylus cantonensis infection.

Angiostrongylus cantonensis (A. cantonensis) is the most common infectious agent causing eosinophilic meningitis. As an important food-borne parasitic disease, angiostrongyliasis cantonensis is an emerging infectious disease which brings severe harm to central nerve system of human. Rat, one of the few permissive hosts of A. cantonensis known to date, plays an indispensable role in the worm's life cycle. However, the tolerance and adaptation of rat to A. cantonensis infection is rarely understood. In this study, we infected rats with different numbers the third stage larvae (L3) of A. cantonensis and explored their tolerance through analysis on survival curve, neurological function score, and detection of pathological damages in organs including the brain, lung, and heart of the animals. Results indicated that rats' survival condition worsens, and body weight dropped more significantly as more worms were used for infection. Death appeared in groups infected with 80 and more A. cantonesnsis per rat. Morris water maze revealed that the neurological function of rats damaged gradually with increasing infection number of A. cantonensis larvae. When the number of infected parasite exceeded 240 per animal, rats showed significant neurological impairments. Collection of A. cantonensis from rat lung after 35days of infection implied an upper limit for worm entry, and the average length of worm was inversely proportional to the infection amount, while the ratio between female and male worms was positively related to the infection number. The degree of pulmonary and cardiac inflammation was proportional to the infection number of A. cantonensis. Meanwhile, there existed considerable amount of adult worms in rat's right atrium and right ventricle, leading to a right heart myocardial inflammation. The present study firstly reports the tolerance and adaptation of rat, a permissive host of A. cantonensis to its infection, which will not only provide accurate technical parameters for maintaining A. cantonensis life cycle under laboratory conditions but also help unveil the underlying mechanism of the distinct pathological outcomes in the permissive and non-permissive hosts with A. cantonensis infection.

Worm structure piezoelectric energy harvester using ionotropic gelation of barium titanate-calcium alginate composite

A laterally aligned flexible composite linear worm-based piezoelectric energy harvester made up of piezoelectric barium titanate nanoparticles and a three dimensional gel network of calcium alginate biopolymer was aimed to harness the low frequency mechanical energy. It is highly desirable to fabricate innovative micro/nanostructures for high performance energy harvesting beyond the conventional thin films, and small scale fabrication of nanowires (or rods). The open circuit voltage of a single composite worm-based energy harvester (diameter ≈ 550 μm, length ≈ 2.5 cm) increases up to 5 times by increasing the frequency of mechanical load (11 N) from 3 to 20 Hz. Similarly, 1.5 times voltage increment was observed by increasing the length of the composite worm from 1.5 to 3.5 cm upon the bio-mechanical hand force. The energy harvester can function as an efficient portable/wearable self-powered device due to its good flexibility, and multiple lengths of composite linear worms can be utilized to drive low-power electronic devices. In this work, the composite worms were prepared by an ionotropic gelation approach, which is eco-friendly, non-toxic, having low processing temperature/time, and potential for cost-effective, large-scale fabrication, making it suitable for low frequency based self-powered devices.

Haemonchus longistipes Railliet & Henry, 1909 (Nematoda, Trichostrongylidae) from the Egyptian dromedary, Camelus dromedarius (Artiodactyla: Camelidae), first identification on the basis of light and ultrastructural data.

Haemonchus longistipes is a gastrointestinal abomasal nematode which is one of the most prevalent and pathogenic parasites infesting the stomach of ruminants. On the basis of light and ultrastructural data, the objective of the present study was to introduce a first identification of the cameline haemonchosis caused by H. longistipes. Abomasa of 42 Egyptian camels Camelus dromedarius (Artiodactyla: Camelidae) were collected monthly from September 2013 to April 2014 from the main slaughter house of Cairo, Egypt. Adult male and female nematode worms were recovered from 26 (62%) specimens of the examined abomasa. The parasites were of yellow color; the body was filiform (slender) tapered towards the anterior end in male and towards both ends in female. Buccal capsules absent, the buccal cavity was small with a conspicuous dorsal lancet extended from dorsal wall. The cervical papillae were prominent and spine-like. The body length of the female worm was 16.6-20.5 (18.5 ± 0.3) mm. The anterior end to the cervical papillae was 3.19-4.30 (4.12 ± 0.5) mm. The vulva of the female had a linguiform process or flap, the tail is without a spine, and the anal pore at the posterior end of the body had a simple dorsal rim. The body of male was 10.4-14.7 (13.9 ± 2.0) mm in length. The male bursa had elongated lobes supported by long, slender rays. The small dorsal lobe was asymmetrical with Y-shaped dorsal rays. The spicules were long with a length of 0.52-0.54 (0.53 ± 0.05) mm, each provided with a small barb and pore near its extremity. Synlophe was bilaterally and dorsoventrally symmetrical; it extended from cephalic expansion over anterior 50% of prebursal or prevulvar body and consisted of a maximum of 42 ridges. The described species herein was compared with the three morphologically similar species Haemonchus mitchelli, Haemonchus okapiae, and H. longistipes with their synlophes consist of 42 ridges distributed over the anterior half of the body. These species can be separated by unique structural characteristics of their synlophes, spicules, and copulatory bursa. The most morphologically similar species to the recovered worm was H. longistipes. Also, some of the parameters with regard to morphology and morphometry of this parasite were described for the first time.

Dynamics and rheology of wormlike micelles emerging from particulate computer simulations

We perform coarse-grained computer simulations of solutions of semidilute wormlike micelles and study their dynamic and rheological properties, both in equilibrium and under shear flow. The simulation model is tailored to the study of relatively large time and length scales (micrometers and several milliseconds), while it still retains the specific mechanical properties of the individual wormlike micelles. The majority of the mechanical properties (persistence length, diameter, and elastic modulus of a single worm) is determined from more detailed atomistic molecular dynamics simulations, providing the link with the chemistry of the surfactants. The method is applied to the case of a solution containing 8% (by weight) erucyl bis(hydroxymethyl)methylammonium chloride (EHAC). Different scission energies ranging from 15.5k(b)T to 19.1k(B)T are studied, leading to both unentangled and entangled wormlike micelles. We find a decrease in the average contour length and an increase in the average breaking rate with increasing shear rate. In equilibrium, the decay of the shear relaxation modulus of the unentangled samples agrees with predictions based on a theory of breakable Rouse chains. Under shear flow, transient over- and undershoots are measured in the stress tensor components. At high shear rates we observe a steady-state shear stress proportional to gamma(1/3), where gamma is the shear rate. This is confirmed by our high shear rate experiments of real EHAC in a parallel-plate geometry.

A child with an acanthocephalan infection

We herein describe a case of acanthocephalan infection in a 20-month old Saudi child who presented with a 3-month history of recurrent passage of long worms and poor appetite. The worm was misdiagnosed as Ascaris at another institution. Careful egg and worm examination confirmed the diagnosis of the acanthocephalan Moniliformis moniliformis. The child completely recovered with two courses of mebendazole, 3 days each, administered one week apart. Repeated stool analysis for 2-months post therapy confirmed complete eradication of this worm. We believe this is the first case of human acanthocephalan infection reported in Saudi Arabia.

Diffuse Unilateral Subacute Neuroretinitis in Africa

Purpose: Diffuse unilateral subacute neuroretinitis (DUSN) is well known in endemic areas of the southeastern United States, South America, and the northern Midwestern United States. Two different categories of nematodes, according to their length, are related to endemic areas. We report the first case of DUSN caused by a small nematode in Africa. Methods: We describe the case of a 12-year-old Senegalese girl who presented a long-standing diffuse unilateral subacute neuroretinitis and in whom the worm could be localized. Results: The length of the unidentified worm measured using the software of the fundus camera was approximately 600 μ m. This measurement corresponds to the smaller nematode usually found in patients from the southeastern United States and South America. Conclusion: Diffuse unilateral subacute neuroretinitis can also be observed in patients living in Africa.

Coordinates, DNA content and heterogeneity of cell nuclei and segments of the Caenorhabditis elegans intestine

A specific protocol allowed to selectively stain and image the cell nuclei of the intestine of the nematode Caenorhabditis elegans. Digital processing of these images yielded quantitative information on the coordinates and the relative DNA content of these cell nuclei. With this technique, the exact locations (in relation to the length of worm or intestine) of the 20 intestinal cell nuclei of larval stage L1 and of the 34 intestinal cell nuclei of larval stages L2-4 and adults were determined. Tracking the DNA content of an individual intestinal cell nuclei allowed to study nuclear DNA endoreduplications during larval growth. The evaluation of the DNA content of all intestinal cell nuclei revealed a strong heterogeneity between the cell nuclei and intestinal segments with a maximum in segments int4-int5 in the L1 stage and int5-int6 in the L2-L4 stages. Minimum values were detected in the segments int2 and int8-int9 of all larval stages. Heterogeneity between the intestinal segments of C. elegans does not only concern the DNA content of cell nuclei, but also other cellular features like the quantity of intracellular vesicles or the absorption of particles out of the intestinal lumen.

External Morphology of the Posterior End, the “Opisthosoma”, of the Beard Worm Oligobrachia mashikoi (Pogonophora)

The entire length of the beard worm, Oligobrachia mashikoi (Pogonophora), including the posterior end, the "opisthosoma" was collected successfully. This species is exclusive to Tsukumo Bay in Ishikawa Prefecture, Japan. Although the portion preceding the opisthosoma was similar to a fine filament, it abruptly assumed a shape similar to a shovel and appeared to be composed of many segmental structures. The number of segments exceeded 50. The dorsal side of the opisthosoma differed from that of the ventral side in morphology. The opisthosoma was equipped with 4 lines of setae arranged longitudinally and a sucker on the tip. When considering the fact that the Family Oligobrachiidae is the most primitive group of pogonophores, the external morphology of the opisthosoma is interesting as it may be reminiscent of the ancestral condition. This is the first report of the opisthosoma in Oligobrachiidae.

Buckling and persistence length of an amphiphilic worm from molecular dynamics simulations

A wormlike micelle of coarse-grained amphiphilic molecules is simulated with molecular dynamics. We demonstrate that our worm is inherently stable, i.e., it does not depend on periodic boundary conditions for its continued survival, which sets it apart from some, and perhaps even all, previously simulated worms. The worms are observed to buckle under sufficiently strong compression forces. The persistence length and bending rigidity follow from analyzing the thermal undulations of a tensionless worm. System size dependencies of the elastic modulus of the worm, as reported for amphiphilic bilayers, are eliminated by explicitly calculating the arc length of the worm.

Inequalities in size and intensity-dependent growth in a mermithid nematode parasitic in beach hoppers.

Inequality in body sizes is a common feature in populations of helminth parasites, with potential consequences for egg production and population genetics. Inequalities in body lengths and the effects of intraspecific competition on worm length were studied in a species of mermithid nematode parasitic in the crustacean Talorchestia quoyana (Amphipoda: Talitridae). The majority of the 753 worms recovered were relatively small, and an analysis using a Lorenz curve and Gini coefficient suggested that there were no marked inequalities in body lengths among the worms. Total worm length in the 356 infected amphipods (i.e. the sum of the lengths of all the worms in a host) increased steadily as a function of the number of worms per amphipod, whereas the length of the longest worm per amphipod peaked in amphipods harbouring intermediate numbers of worms. This last result was not significantly accounted for by the observed increase in host size with increasing intensity of infection, but resulted from a correlation between worm length and host size. As the number of worms per amphipod increased, the relative sizes of the second-, third-, and fourth-longest worms per host increased markedly. This means that relative inequalities in sizes become less pronounced, i.e. subordinate worms get closer in size to the longest worm, as the number of worms per host increases. The main consequence of this phenomenon is that worm sizes in the mermithid population are more homogeneous than they would be if intraspecific competition had stronger effects on worm growth.

Partial cross-resistance between Strongyloides venezuelensis and Nippostrongylus brasiliensis in rats.

Rats were immunized through an initial infection with 1,000 filariform larvae (L3) of Nippostrongylus brasiliensis and after complete expulsion of worms they were challenged with 1,000 L3 of Strongyloides venezuelensis to investigate whether cross-resistance developed against a heterologous parasite. Nippostrongylus brasiliensis-immunized rats developed a partial cross-resistance against S. venezuelensis migrating larvae (MSL3) in the lungs and adult worms in the small intestine. The population of MSL3 in the lungs were significantly lower (P < 0.05) in immunized rats (22.0 +/- 7.4) compared with controls (105.0 +/- 27.6). The populations of adult worms, egg output and fecundity were initially decreased but from day 14 post-challenge they did not show any significant difference between immunized and control rats. However, the length of worm in immunized rat was revealed as retardation. Peripheral blood eosinophilia was significantly decreased (P < 0.05) on day 7 post-challenge and then gradually increased, which peaked on day 42 post-challenge when most of the worms were expelled. These results suggest that peripheral blood eosinophilia is strongly involved in the worm establishment and expulsion mechanisms.

The occurrence of the eunicid polychaetesIphitime cuenotiFauvel andI. PaguriFage &amp; legendre in crabs from the Scottish West Coast

Abstract During an investigation into the occurrence of various crab species in the Oban (West of Scotland) area, Iphitime cuenoti was found infesting the branchial cavity of Liocarcinus puber, L. corrugatus, L. depurator, Carcinus mamas, Cancer pagurus, Hyas araneus and Macropodia longirostris caught within, or on the sandy mud below, the Laminaria forest. The same crab species obtained from sandy habitats, and crabs peculiar to such a habitat (Portumnus latipes, Liocarcinus holsatus and Corystes cassivelaunus) did not harbour the polychaetes. Three or more worms were commonly found in each Liocarcinus host, the highest number recorded, in L. puber, comprising 9 adult and at least 98 juveniles, the latter being found between the gill lamellae. Over 90% of both L. puber and L. corrugatus were infested, 35% of L. depuratot, but less than 10% of any of the other species. The largest worms (up to 80 mm alcohol-preserved length) were found in L. puber and L. corrugatus. Worms were found to have either simple or slightly bifurcate branchiae, or multifurcate branchiae. Worms with simple branchiae rarely reached 40 mm in length, usually possessed jaws which exceeded 700 μm in length, and were never found to contain eggs. These are regarded as putative males, and histological evidence from three specimens confirms this suggestion. Only Iphitime with multifurcate branchiae were found to contain eggs, and were also the largest worms, but their jaw length was very variable, ranging from 0-1030 μm with little or no relationship to the length of the worm. The smallest worms, 3 mm in length, were found between the gill lamellae throughout the year, but mainly from December to August. In multiple infestations there appeared to be one dominant female which probably inhibited maturation of companion worms, and it is postulated that once this female vacates, there is a sequential maturation and spawning of subordinate worms. The greatest number of mature worms, and the largest worms, occurred during October and November, but because of the extended larval settlement period it is a matter of debate whether the worm is an annual, or has a more extended lifetime. Iphitime paguri was found occupying the apical whorl of4.6% of Buccinum undatum shells and 2.6% of Neptunea antiqua shells occupied by the hermit crab Eupagurus bernhardus. The worm is very fragile and, being rare, there is insufficient data to define its biology. The longest worm was 50 mm (alcohol- preserved length) and the largest jaw length 760 μm; there appeared to be an inverse relationship between length of worm and jaw size, and no worm over 25 mm had jaws larger than 250 μm. All ovigerous worms had small jaws. Nereis fucata was found in 2.6% of Neptunea antiqua and 7.1% of Buccinum undatum shells occupied by the hermit crab. It was not found associated with Iphitime paguri.

Wahlia pulchella n. sp., a Turbellarian Flatworm (Neorhabdocoela: Umagillidae) from the Intestine of the Sea Cucumber Stichopus californicus

Wahlia pulchella n. sp. is described from the intestine of the aspidochirote holothuroid Stichopus californicus. The new species differs from other members of the genus in having the following combination of features: the pharynx lies at the end of the first quarter or third of the body, the intestine extends anterior to the brain, the testes are only slightly lobed, and the penis stylet is straight and less than half the length of the adult worm. Wahlia pulchella has a "secondary uterus" in which there may be up to 12 egg capsules. The validity of the genera of holothuroid-inhabiting umagillids characterized by 2 ovaries and a secondary uterus is discussed. It is suggested that Ozametra Marcus, 1949, be placed in synonymy under Wahlia Westblad, 1930. New diagnoses of Wahlia and Seritia Cannon, 1982, are presented.

Fecundity of Litomosoides carinii (Nematoda, Filarioidea) in vivo and in vitro.

Several parameters concerning the reproduction of Litomosoides carinii were assessed using quantitatively infected cotton rats (Sigmodon hispidus). The course of embryogenesis from the fertilization of eggs to the delivery of the first microfilariae was observed by daily autopsies during prepatency. The duration of embryogenesis in vivo could thus be determined as 18 +/- 2 days. The contents of embryos in the uteri of female worms had been examined at various intervals. At the onset of patency 7-8 weeks p.i. the females were 71 +/- 6 mm long and on average contained 308 X 10(3) embryos/female, of which 19% were pathologically altered. In the middle of patency 16-20 weeks p.i. the females had grown up to 100 +/- 11 mm in length and now contained 509 X 10(3) embryos/female, 25% of them were pathologically altered, the others were normally developed. A positive correlation between the body length of a female worm and its number of embryos in utero was evident. Additionally the percentage of pathologically altered embryos was increased with respect to the age of the worms. The calculated fecundity of a female L. carinii in vivo of around 20 X 10(3) microfilariae/female per day had been confirmed with worms maintained in vitro. Three combinations of media and serum supplements were used and their influence on embryogenesis evaluated.

Distribution of residence time of material being processed over the zones in type SN reactor-mixers

Previous equations given for calculating the mean residence time of material being processed in the mixing chamber of continuous reactor-mixers show the effect on residence time of the capacity and mean reactor-mixer filling factor, the filling factor of the worm conveyor, and the mixer volume. It is necessary to take into account that such reactors operate only with ''starvation'' of the feed zone with charge. In this case the injected composition of the initial components is not disturbed. The filling factor in the zones of the guard coils of the conveyor worm becomes equal to unity over the length of the worm equal to double the length of the guard coil zones with different pitches of the guard and conveying coils. Consequently, the time of residence is not distributed uniformly over the length of the mixer but in proportion to the number of zones and the number of guard coils in the zones which are characteristic also for the mean filling factor. Experiments have been conducted in a type SN-100 reactor-mixer with an open body. After stopping the unit the upper half of the casing was opened without destroying the distribution of the material over the zones and turns ofmore » the worm. The material was removed from each zone, and the quantities were used to calculate the filling fatrors. The experimental filling factors were used to calculate the residence times of the material in the zones, the distribution of the times over the zones, and the mean residence time of the material in the mixer. The results obtained differed by not more than 5% from calculated values.« less